diff --git a/apps/openmw/mwbase/mechanicsmanager.hpp b/apps/openmw/mwbase/mechanicsmanager.hpp
index 750fc2fff8..9f9b5af701 100644
--- a/apps/openmw/mwbase/mechanicsmanager.hpp
+++ b/apps/openmw/mwbase/mechanicsmanager.hpp
@@ -76,6 +76,12 @@ namespace MWBase
 
             virtual void restoreDynamicStats() = 0;
             ///< If the player is sleeping, this should be called every hour.
+
+            virtual int getBarterOffer(const MWWorld::Ptr& ptr,int basePrice, bool buying) = 0;
+            ///< This is used by every service to determine the price of objects given the trading skills of the player and NPC.
+
+            virtual int getDerivedDisposition(const MWWorld::Ptr& ptr) = 0;
+            ///< Calculate the diposition of an NPC toward the player.
             
             virtual int countDeaths (const std::string& id) const = 0;
             ///< Return the number of deaths for actors with the given ID.
diff --git a/apps/openmw/mwclass/npc.cpp b/apps/openmw/mwclass/npc.cpp
index e58de6079f..6a516bcc80 100644
--- a/apps/openmw/mwclass/npc.cpp
+++ b/apps/openmw/mwclass/npc.cpp
@@ -95,6 +95,7 @@ namespace MWClass
                 data->mCreatureStats.setFatigue (ref->mBase->mNpdt52.mFatigue);
 
                 data->mCreatureStats.setLevel(ref->mBase->mNpdt52.mLevel);
+                data->mNpcStats.setDisposition(ref->mBase->mNpdt52.mDisposition);
             }
             else
             {
diff --git a/apps/openmw/mwdialogue/dialoguemanagerimp.cpp b/apps/openmw/mwdialogue/dialoguemanagerimp.cpp
index 7e9525e61b..46fab0a4b4 100644
--- a/apps/openmw/mwdialogue/dialoguemanagerimp.cpp
+++ b/apps/openmw/mwdialogue/dialoguemanagerimp.cpp
@@ -804,7 +804,7 @@ namespace MWDialogue
             || services & ESM::NPC::Misc)
             windowServices |= MWGui::DialogueWindow::Service_Trade;
 
-        if( !mActor.get<ESM::NPC>()->mBase->mTransport.empty())
+        if(mActor.getTypeName() == typeid(ESM::NPC).name() && !mActor.get<ESM::NPC>()->mBase->mTransport.empty())
             windowServices |= MWGui::DialogueWindow::Service_Travel;
 
         if (services & ESM::NPC::Spells)
diff --git a/apps/openmw/mwgui/dialogue.cpp b/apps/openmw/mwgui/dialogue.cpp
index b8022f6299..e1baaf8e00 100644
--- a/apps/openmw/mwgui/dialogue.cpp
+++ b/apps/openmw/mwgui/dialogue.cpp
@@ -12,6 +12,7 @@
 #include "../mwbase/dialoguemanager.hpp"
 #include "../mwbase/world.hpp"
 #include "../mwbase/windowmanager.hpp"
+#include "../mwbase/mechanicsmanager.hpp"
 
 #include "dialogue_history.hpp"
 #include "widgets.hpp"
@@ -50,7 +51,7 @@ std::string::size_type find_str_ci(const std::string& str, const std::string& su
 
 DialogueWindow::DialogueWindow(MWBase::WindowManager& parWindowManager)
     : WindowBase("openmw_dialogue_window.layout", parWindowManager)
-    , mEnabled(true)
+    , mEnabled(false)
     , mServices(0)
 {
     // Centre dialog
@@ -299,10 +300,13 @@ void DialogueWindow::updateOptions()
     mTopicsList->clear();
     mHistory->eraseText(0, mHistory->getTextLength());
 
-    mDispositionBar->setProgressRange(100);
-    mDispositionBar->setProgressPosition(40);
-    mDispositionText->eraseText(0, mDispositionText->getTextLength());
-    mDispositionText->addText("#B29154"+std::string("40/100")+"#B29154");
+    if (mPtr.getTypeName() == typeid(ESM::NPC).name())
+    {
+        mDispositionBar->setProgressRange(100);
+        mDispositionBar->setProgressPosition(MWBase::Environment::get().getMechanicsManager()->getDerivedDisposition(mPtr));
+        mDispositionText->eraseText(0, mDispositionText->getTextLength());
+        mDispositionText->addText("#B29154"+boost::lexical_cast<std::string>(MWBase::Environment::get().getMechanicsManager()->getDerivedDisposition(mPtr))+std::string("/100")+"#B29154");
+    }
 }
 
 void DialogueWindow::goodbye()
@@ -316,3 +320,14 @@ void DialogueWindow::onReferenceUnavailable()
 {
     mWindowManager.removeGuiMode(GM_Dialogue);
 }
+
+void DialogueWindow::onFrame()
+{
+    if(mEnabled && mPtr.getTypeName() == typeid(ESM::NPC).name())
+    {
+        mDispositionBar->setProgressRange(100);
+        mDispositionBar->setProgressPosition(MWBase::Environment::get().getMechanicsManager()->getDerivedDisposition(mPtr));
+        mDispositionText->eraseText(0, mDispositionText->getTextLength());
+        mDispositionText->addText("#B29154"+boost::lexical_cast<std::string>(MWBase::Environment::get().getMechanicsManager()->getDerivedDisposition(mPtr))+std::string("/100")+"#B29154");
+    }
+}
diff --git a/apps/openmw/mwgui/dialogue.hpp b/apps/openmw/mwgui/dialogue.hpp
index 3a89409cac..bb9acf5db9 100644
--- a/apps/openmw/mwgui/dialogue.hpp
+++ b/apps/openmw/mwgui/dialogue.hpp
@@ -47,6 +47,7 @@ namespace MWGui
         void addTitle(std::string text);
         void askQuestion(std::string question);
         void goodbye();
+        void onFrame();
 
         // make sure to call these before setKeywords()
         void setServices(int services) { mServices = services; }
diff --git a/apps/openmw/mwgui/spellbuyingwindow.cpp b/apps/openmw/mwgui/spellbuyingwindow.cpp
index 813a21b122..a41f401a57 100644
--- a/apps/openmw/mwgui/spellbuyingwindow.cpp
+++ b/apps/openmw/mwgui/spellbuyingwindow.cpp
@@ -8,6 +8,7 @@
 #include "../mwbase/world.hpp"
 #include "../mwbase/soundmanager.hpp"
 #include "../mwbase/windowmanager.hpp"
+#include "../mwbase/mechanicsmanager.hpp"
 
 #include "../mwworld/player.hpp"
 #include "../mwworld/manualref.hpp"
@@ -52,9 +53,9 @@ namespace MWGui
         const MWWorld::ESMStore &store =
             MWBase::Environment::get().getWorld()->getStore();
 
-        const ESM::Spell* spell = store.get<ESM::Spell>().find(spellId);
-
+        const ESM::Spell* spell = MWBase::Environment::get().getWorld()->getStore().get<ESM::Spell>().find(spellId);
         int price = spell->mData.mCost*store.get<ESM::GameSetting>().find("fSpellValueMult")->getFloat();
+        price = MWBase::Environment::get().getMechanicsManager()->getBarterOffer(mPtr,price,true);
 
         MyGUI::Button* toAdd =
             mSpellsView->createWidget<MyGUI::Button>(
@@ -67,7 +68,6 @@ namespace MWGui
             );
 
         mCurrentY += sLineHeight;
-        /// \todo price adjustment depending on merchantile skill
 
         toAdd->setUserData(price);
         toAdd->setCaptionWithReplacing(spell->mName+"   -   "+boost::lexical_cast<std::string>(price)+"#{sgp}");
diff --git a/apps/openmw/mwgui/spellcreationdialog.cpp b/apps/openmw/mwgui/spellcreationdialog.cpp
index 25af72c50d..69d69519f9 100644
--- a/apps/openmw/mwgui/spellcreationdialog.cpp
+++ b/apps/openmw/mwgui/spellcreationdialog.cpp
@@ -7,6 +7,7 @@
 #include "../mwbase/world.hpp"
 #include "../mwbase/environment.hpp"
 #include "../mwbase/soundmanager.hpp"
+#include "../mwbase/mechanicsmanager.hpp"
 
 #include "../mwworld/esmstore.hpp"
 #include "../mwworld/player.hpp"
@@ -399,8 +400,7 @@ namespace MWGui
         float fSpellMakingValueMult =
             store.get<ESM::GameSetting>().find("fSpellMakingValueMult")->getFloat();
 
-        /// \todo mercantile
-        int price = int(y) * fSpellMakingValueMult;
+        int price = MWBase::Environment::get().getMechanicsManager()->getBarterOffer(mPtr,int(y) * fSpellMakingValueMult,true);
 
         mPriceLabel->setCaption(boost::lexical_cast<std::string>(int(price)));
 
diff --git a/apps/openmw/mwgui/tradewindow.cpp b/apps/openmw/mwgui/tradewindow.cpp
index 6498cd7120..0707ad985a 100644
--- a/apps/openmw/mwgui/tradewindow.cpp
+++ b/apps/openmw/mwgui/tradewindow.cpp
@@ -6,10 +6,16 @@
 #include "../mwbase/world.hpp"
 #include "../mwbase/soundmanager.hpp"
 #include "../mwbase/windowmanager.hpp"
+#include "../mwbase/mechanicsmanager.hpp"
 
 #include "../mwworld/inventorystore.hpp"
 #include "../mwworld/manualref.hpp"
 
+#include "../mwmechanics/creaturestats.hpp"
+#include "../mwmechanics/npcstats.hpp"
+
+#include "../mwworld/player.hpp"
+
 #include "inventorywindow.hpp"
 
 namespace MWGui
@@ -52,6 +58,8 @@ namespace MWGui
 
         mCancelButton->eventMouseButtonClick += MyGUI::newDelegate(this, &TradeWindow::onCancelButtonClicked);
         mOfferButton->eventMouseButtonClick += MyGUI::newDelegate(this, &TradeWindow::onOfferButtonClicked);
+        mIncreaseButton->eventMouseButtonClick += MyGUI::newDelegate(this, &TradeWindow::onIncreaseButtonClicked);
+        mDecreaseButton->eventMouseButtonClick += MyGUI::newDelegate(this, &TradeWindow::onDecreaseButtonClicked);
 
         setCoord(400, 0, 400, 300);
 
@@ -63,6 +71,7 @@ namespace MWGui
         setTitle(MWWorld::Class::get(actor).getName(actor));
 
         mCurrentBalance = 0;
+        mCurrentMerchantOffer = 0;
 
         mWindowManager.getInventoryWindow()->startTrade();
 
@@ -135,6 +144,9 @@ namespace MWGui
 
     void TradeWindow::onOfferButtonClicked(MyGUI::Widget* _sender)
     {
+        const MWWorld::Store<ESM::GameSetting> &gmst =
+            MWBase::Environment::get().getWorld()->getStore().get<ESM::GameSetting>();
+
         // were there any items traded at all?
         MWWorld::ContainerStore& playerBought = mWindowManager.getInventoryWindow()->getBoughtItems();
         MWWorld::ContainerStore& merchantBought = getBoughtItems();
@@ -178,6 +190,56 @@ namespace MWGui
             return;
         }
 
+        if(mCurrentBalance > mCurrentMerchantOffer)
+        {
+            //if npc is a creature: reject (no haggle)
+            if (mPtr.getTypeName() != typeid(ESM::NPC).name())
+            {
+                MWBase::Environment::get().getWindowManager()->
+                    messageBox("#{sNotifyMessage9}", std::vector<std::string>());
+                return;
+            }
+
+            int a = abs(mCurrentMerchantOffer);
+            int b = abs(mCurrentBalance);
+            int d = 0;
+            if (mCurrentMerchantOffer<0) d = int(100 * (a - b) / a);
+            else d = int(100 * (b - a) / a);
+
+            float clampedDisposition = std::max<int>(0,std::min<int>(int(MWBase::Environment::get().getMechanicsManager()->getDerivedDisposition(mPtr)),100));
+
+            MWMechanics::NpcStats sellerSkill = MWWorld::Class::get(mPtr).getNpcStats(mPtr);
+            MWMechanics::CreatureStats sellerStats = MWWorld::Class::get(mPtr).getCreatureStats(mPtr); 
+            MWWorld::Ptr playerPtr = MWBase::Environment::get().getWorld()->getPlayer().getPlayer();
+            MWMechanics::NpcStats playerSkill = MWWorld::Class::get(playerPtr).getNpcStats(playerPtr);
+            MWMechanics::CreatureStats playerStats = MWWorld::Class::get(playerPtr).getCreatureStats(playerPtr);
+
+            float a1 = std::min(playerSkill.getSkill(ESM::Skill::Mercantile).getModified(), 100.f);
+            float b1 = std::min(0.1f * playerStats.getAttribute(ESM::Attribute::Luck).getModified(), 10.f);
+            float c1 = std::min(0.2f * playerStats.getAttribute(ESM::Attribute::Personality).getModified(), 10.f);
+            float d1 = std::min(sellerSkill.getSkill(ESM::Skill::Mercantile).getModified(), 100.f);
+            float e1 = std::min(0.1f * sellerStats.getAttribute(ESM::Attribute::Luck).getModified(), 10.f);
+            float f1 = std::min(0.2f * sellerStats.getAttribute(ESM::Attribute::Personality).getModified(), 10.f);
+
+            float pcTerm = (clampedDisposition - 50 + a1 + b1 + c1) * playerStats.getFatigueTerm();
+            float npcTerm = (d1 + e1 + f1) * sellerStats.getFatigueTerm();
+            float x = gmst.find("fBargainOfferMulti")->getFloat() * d + gmst.find("fBargainOfferBase")->getFloat();
+            if (mCurrentMerchantOffer<0) x += abs(int(pcTerm - npcTerm));
+            else x += abs(int(npcTerm - pcTerm));
+
+            int roll = std::rand()%100 + 1;
+            if(roll > x) //trade refused
+            {
+                MWBase::Environment::get().getWindowManager()->
+                    messageBox("#{sNotifyMessage9}", std::vector<std::string>());
+                /// \todo adjust npc temporary disposition by iBarterSuccessDisposition or iBarterFailDisposition
+                return ;
+            }
+        }
+
+
+/// \todo adjust npc temporary disposition by iBarterSuccessDisposition or iBarterFailDisposition
+
         // success! make the item transfer.
         transferBoughtItems();
         mWindowManager.getInventoryWindow()->transferBoughtItems();
@@ -202,6 +264,20 @@ namespace MWGui
         mWindowManager.removeGuiMode(GM_Barter);
     }
 
+    void TradeWindow::onIncreaseButtonClicked(MyGUI::Widget* _sender)
+    {
+        if(mCurrentBalance<=-1) mCurrentBalance -= 1;
+        if(mCurrentBalance>=1) mCurrentBalance += 1;
+        updateLabels();
+    }
+
+    void TradeWindow::onDecreaseButtonClicked(MyGUI::Widget* _sender)
+    {
+        if(mCurrentBalance<-1) mCurrentBalance += 1;
+        if(mCurrentBalance>1) mCurrentBalance -= 1;
+        updateLabels();
+    }
+
     void TradeWindow::updateLabels()
     {
         mPlayerGold->setCaptionWithReplacing("#{sYourGold} " + boost::lexical_cast<std::string>(mWindowManager.getInventoryWindow()->getPlayerGold()));
@@ -320,19 +396,17 @@ namespace MWGui
 
     void TradeWindow::sellToNpc(MWWorld::Ptr item, int count)
     {
-        /// \todo price adjustment depending on merchantile skill
-
-        mCurrentBalance -= MWWorld::Class::get(item).getValue(item) * count;
 
+        mCurrentBalance -= MWBase::Environment::get().getMechanicsManager()->getBarterOffer(mPtr, MWWorld::Class::get(item).getValue(item) * count,true);
+        mCurrentMerchantOffer -= MWBase::Environment::get().getMechanicsManager()->getBarterOffer(mPtr, MWWorld::Class::get(item).getValue(item) * count,true);
         updateLabels();
     }
 
     void TradeWindow::buyFromNpc(MWWorld::Ptr item, int count)
     {
-        /// \todo price adjustment depending on merchantile skill
-
-        mCurrentBalance += MWWorld::Class::get(item).getValue(item) * count;
 
+        mCurrentBalance += MWBase::Environment::get().getMechanicsManager()->getBarterOffer(mPtr, MWWorld::Class::get(item).getValue(item) * count,false);
+        mCurrentMerchantOffer += MWBase::Environment::get().getMechanicsManager()->getBarterOffer(mPtr, MWWorld::Class::get(item).getValue(item) * count,false);
         updateLabels();
     }
 
diff --git a/apps/openmw/mwgui/tradewindow.hpp b/apps/openmw/mwgui/tradewindow.hpp
index 4ec55045c5..db386d8b6f 100644
--- a/apps/openmw/mwgui/tradewindow.hpp
+++ b/apps/openmw/mwgui/tradewindow.hpp
@@ -55,11 +55,14 @@ namespace MWGui
             MyGUI::TextBox* mMerchantGold;
 
             int mCurrentBalance;
+            int mCurrentMerchantOffer;
 
             void onWindowResize(MyGUI::Window* _sender);
             void onFilterChanged(MyGUI::Widget* _sender);
             void onOfferButtonClicked(MyGUI::Widget* _sender);
             void onCancelButtonClicked(MyGUI::Widget* _sender);
+            void onIncreaseButtonClicked(MyGUI::Widget* _sender);
+            void onDecreaseButtonClicked(MyGUI::Widget* _sender);
 
             // don't show items that the NPC has equipped in his trade-window.
             virtual bool ignoreEquippedItems() { return true; }
diff --git a/apps/openmw/mwgui/trainingwindow.cpp b/apps/openmw/mwgui/trainingwindow.cpp
index 1e9841afb0..ba39ee601c 100644
--- a/apps/openmw/mwgui/trainingwindow.cpp
+++ b/apps/openmw/mwgui/trainingwindow.cpp
@@ -7,6 +7,7 @@
 #include "../mwbase/windowmanager.hpp"
 #include "../mwbase/environment.hpp"
 #include "../mwbase/world.hpp"
+#include "../mwbase/mechanicsmanager.hpp"
 
 #include "../mwworld/player.hpp"
 
@@ -78,8 +79,8 @@ namespace MWGui
 
         for (int i=0; i<3; ++i)
         {
-            /// \todo mercantile skill
-            int price = pcStats.getSkill (bestSkills[i].first).getBase() * gmst.find("iTrainingMod")->getInt ();
+            int price = MWBase::Environment::get().getMechanicsManager()->getBarterOffer
+                    (mPtr,pcStats.getSkill (bestSkills[i].first).getBase() * gmst.find("iTrainingMod")->getInt (),true);
 
             std::string skin = (price > mWindowManager.getInventoryWindow ()->getPlayerGold ()) ? "SandTextGreyedOut" : "SandTextButton";
 
@@ -119,8 +120,8 @@ namespace MWGui
         const MWWorld::ESMStore &store =
             MWBase::Environment::get().getWorld()->getStore();
 
-        /// \todo mercantile skill
         int price = pcStats.getSkill (skillId).getBase() * store.get<ESM::GameSetting>().find("iTrainingMod")->getInt ();
+        price = MWBase::Environment::get().getMechanicsManager()->getBarterOffer(mPtr,price,true);
 
         if (mWindowManager.getInventoryWindow()->getPlayerGold()<price)
             return;
diff --git a/apps/openmw/mwgui/travelwindow.cpp b/apps/openmw/mwgui/travelwindow.cpp
index 0e7ebaaa3e..abbc6172fe 100644
--- a/apps/openmw/mwgui/travelwindow.cpp
+++ b/apps/openmw/mwgui/travelwindow.cpp
@@ -69,9 +69,10 @@ namespace MWGui
             price = d/gmst.find("fTravelMult")->getFloat();
         }
 
+        price = MWBase::Environment::get().getMechanicsManager()->getBarterOffer(mPtr,price,true);
+
         MyGUI::Button* toAdd = mDestinationsView->createWidget<MyGUI::Button>((price>mWindowManager.getInventoryWindow()->getPlayerGold()) ? "SandTextGreyedOut" : "SandTextButton", 0, mCurrentY, 200, sLineHeight, MyGUI::Align::Default);
         mCurrentY += sLineHeight;
-        /// \todo price adjustment depending on merchantile skill
         if(interior)
             toAdd->setUserString("interior","y");
         else
diff --git a/apps/openmw/mwgui/windowmanagerimp.cpp b/apps/openmw/mwgui/windowmanagerimp.cpp
index 95356f77f5..963a1fe175 100644
--- a/apps/openmw/mwgui/windowmanagerimp.cpp
+++ b/apps/openmw/mwgui/windowmanagerimp.cpp
@@ -582,6 +582,8 @@ void WindowManager::onFrame (float frameDuration)
         mDragAndDrop->mDraggedWidget->setPosition(MyGUI::InputManager::getInstance().getMousePosition());
     }
 
+    mDialogueWindow->onFrame();
+
     mInventoryWindow->onFrame();
 
     mStatsWindow->onFrame();
diff --git a/apps/openmw/mwmechanics/mechanicsmanagerimp.cpp b/apps/openmw/mwmechanics/mechanicsmanagerimp.cpp
index 50868eeb35..3b5a80ef38 100644
--- a/apps/openmw/mwmechanics/mechanicsmanagerimp.cpp
+++ b/apps/openmw/mwmechanics/mechanicsmanagerimp.cpp
@@ -378,6 +378,111 @@ namespace MWMechanics
         mUpdatePlayer = true;
     }
 
+    std::string toLower (const std::string& name)
+    {
+        std::string lowerCase;
+
+        std::transform (name.begin(), name.end(), std::back_inserter (lowerCase),
+            (int(*)(int)) std::tolower);
+
+        return lowerCase;
+    }
+
+    int MechanicsManager::getDerivedDisposition(const MWWorld::Ptr& ptr)
+    {
+        MWMechanics::NpcStats npcSkill = MWWorld::Class::get(ptr).getNpcStats(ptr);
+        float x = npcSkill.getDisposition();
+
+        MWWorld::LiveCellRef<ESM::NPC>* npc = ptr.get<ESM::NPC>();
+        MWWorld::Ptr playerPtr = MWBase::Environment::get().getWorld()->getPlayer().getPlayer();
+        MWWorld::LiveCellRef<ESM::NPC>* player = playerPtr.get<ESM::NPC>();
+        MWMechanics::CreatureStats playerStats = MWWorld::Class::get(playerPtr).getCreatureStats(playerPtr);
+        MWMechanics::NpcStats playerSkill = MWWorld::Class::get(playerPtr).getNpcStats(playerPtr);
+
+        if (toLower(npc->mBase->mRace) == toLower(player->mBase->mRace)) x += MWBase::Environment::get().getWorld()->getStore().get<ESM::GameSetting>().find("fDispRaceMod")->getFloat();
+
+        x += MWBase::Environment::get().getWorld()->getStore().get<ESM::GameSetting>().find("fDispPersonalityMult")->getFloat()
+            * (playerStats.getAttribute(ESM::Attribute::Personality).getModified() - MWBase::Environment::get().getWorld()->getStore().get<ESM::GameSetting>().find("fDispPersonalityBase")->getFloat());
+
+        float reaction = 0;
+        int rank = 0;
+        std::string npcFaction = "";
+        if(!npcSkill.getFactionRanks().empty()) npcFaction = npcSkill.getFactionRanks().begin()->first;
+
+        if (playerSkill.getFactionRanks().find(toLower(npcFaction)) != playerSkill.getFactionRanks().end())
+        {
+            for(std::vector<ESM::Faction::Reaction>::const_iterator it = MWBase::Environment::get().getWorld()->getStore().get<ESM::Faction>().find(toLower(npcFaction))->mReactions.begin();
+                it != MWBase::Environment::get().getWorld()->getStore().get<ESM::Faction>().find(toLower(npcFaction))->mReactions.end(); it++)
+            {
+                if(toLower(it->mFaction) == toLower(npcFaction)) reaction = it->mReaction;
+            }
+            rank = playerSkill.getFactionRanks().find(toLower(npcFaction))->second;
+        }
+        else if (npcFaction != "")
+        {
+            for(std::vector<ESM::Faction::Reaction>::const_iterator it = MWBase::Environment::get().getWorld()->getStore().get<ESM::Faction>().find(toLower(npcFaction))->mReactions.begin();
+                it != MWBase::Environment::get().getWorld()->getStore().get<ESM::Faction>().find(toLower(npcFaction))->mReactions.end();it++)
+            {
+                if(playerSkill.getFactionRanks().find(toLower(it->mFaction)) != playerSkill.getFactionRanks().end() )
+                {
+                    if(it->mReaction<reaction) reaction = it->mReaction;
+                }
+            }
+            rank = 0;
+        }
+        else
+        {
+            reaction = 0;
+            rank = 0;
+        }
+        x += (MWBase::Environment::get().getWorld()->getStore().get<ESM::GameSetting>().find("fDispFactionRankMult")->getFloat() * rank
+            + MWBase::Environment::get().getWorld()->getStore().get<ESM::GameSetting>().find("fDispFactionRankBase")->getFloat())
+            * MWBase::Environment::get().getWorld()->getStore().get<ESM::GameSetting>().find("fDispFactionMod")->getFloat() * reaction;
+
+        /// \todo implement bounty and disease
+        //x -= MWBase::Environment::get().getWorld()->getStore().get<ESM::GameSetting>().find("fDispCrimeMod") * pcBounty;
+        //if (pc has a disease) x += MWBase::Environment::get().getWorld()->getStore().get<ESM::GameSetting>().find("fDispDiseaseMod");
+        if (playerSkill.getDrawState() == MWMechanics::DrawState_::DrawState_Weapon) x += MWBase::Environment::get().getWorld()->getStore().get<ESM::GameSetting>().find("fDispWeaponDrawn")->getFloat();
+
+        int effective_disposition = std::max(0,std::min(int(x),100));//, normally clamped to [0..100] when used
+        return effective_disposition;
+    }
+
+    int MechanicsManager::getBarterOffer(const MWWorld::Ptr& ptr,int basePrice, bool buying)
+    {
+        if (ptr.getTypeName() == typeid(ESM::Creature).name())
+            return basePrice;
+
+        MWMechanics::NpcStats sellerSkill = MWWorld::Class::get(ptr).getNpcStats(ptr);
+        MWMechanics::CreatureStats sellerStats = MWWorld::Class::get(ptr).getCreatureStats(ptr); 
+
+        MWWorld::Ptr playerPtr = MWBase::Environment::get().getWorld()->getPlayer().getPlayer();
+        MWMechanics::NpcStats playerSkill = MWWorld::Class::get(playerPtr).getNpcStats(playerPtr);
+        MWMechanics::CreatureStats playerStats = MWWorld::Class::get(playerPtr).getCreatureStats(playerPtr);
+
+        int clampedDisposition = std::min(getDerivedDisposition(ptr),100);
+        float a = std::min(playerSkill.getSkill(ESM::Skill::Mercantile).getModified(), 100.f);
+        float b = std::min(0.1f * playerStats.getAttribute(ESM::Attribute::Luck).getModified(), 10.f);
+        float c = std::min(0.2f * playerStats.getAttribute(ESM::Attribute::Personality).getModified(), 10.f);
+        float d = std::min(sellerSkill.getSkill(ESM::Skill::Mercantile).getModified(), 100.f);
+        float e = std::min(0.1f * sellerStats.getAttribute(ESM::Attribute::Luck).getModified(), 10.f);
+        float f = std::min(0.2f * sellerStats.getAttribute(ESM::Attribute::Personality).getModified(), 10.f);
+ 
+        float pcTerm = (clampedDisposition - 50 + a + b + c) * playerStats.getFatigueTerm();
+        float npcTerm = (d + e + f) * sellerStats.getFatigueTerm();
+        float buyTerm = 0.01 * (100 - 0.5 * (pcTerm - npcTerm));
+        float sellTerm = 0.01 * (50 - 0.5 * (npcTerm - pcTerm));
+
+        float x; 
+        if(buying) x = buyTerm;
+        else x = std::min(buyTerm, sellTerm);
+        int offerPrice;
+        if (x < 1) offerPrice = int(x * basePrice);
+        if (x >= 1) offerPrice = basePrice + int((x - 1) * basePrice);
+        offerPrice = std::max(1, offerPrice);
+        return offerPrice;
+    }
+
     int MechanicsManager::countDeaths (const std::string& id) const
     {
         return mActors.countDeaths (id);
diff --git a/apps/openmw/mwmechanics/mechanicsmanagerimp.hpp b/apps/openmw/mwmechanics/mechanicsmanagerimp.hpp
index 38536d3bd7..0344d951cc 100644
--- a/apps/openmw/mwmechanics/mechanicsmanagerimp.hpp
+++ b/apps/openmw/mwmechanics/mechanicsmanagerimp.hpp
@@ -79,6 +79,12 @@ namespace MWMechanics
             virtual void restoreDynamicStats();
             ///< If the player is sleeping, this should be called every hour.
 
+            virtual int getBarterOffer(const MWWorld::Ptr& ptr,int basePrice, bool buying);
+            ///< This is used by every service to determine the price of objects given the trading skills of the player and NPC.
+
+            virtual int getDerivedDisposition(const MWWorld::Ptr& ptr);
+            ///< Calculate the diposition of an NPC toward the player.
+
             virtual int countDeaths (const std::string& id) const;
             ///< Return the number of deaths for actors with the given ID.
             
diff --git a/apps/openmw/mwmechanics/npcstats.cpp b/apps/openmw/mwmechanics/npcstats.cpp
index c330cccc8b..5b2ce739f2 100644
--- a/apps/openmw/mwmechanics/npcstats.cpp
+++ b/apps/openmw/mwmechanics/npcstats.cpp
@@ -19,7 +19,8 @@
 
 MWMechanics::NpcStats::NpcStats()
 : mMovementFlags (0), mDrawState (DrawState_Nothing), mBounty (0)
-, mLevelProgress(0)
+, mLevelProgress(0), mDisposition(0)
+
 {
     mSkillIncreases.resize (ESM::Attribute::Length);
     for (int i=0; i<ESM::Attribute::Length; ++i)
@@ -36,6 +37,16 @@ void MWMechanics::NpcStats::setDrawState (DrawState_ state)
     mDrawState = state;
 }
 
+int MWMechanics::NpcStats::getDisposition() const
+{
+    return mDisposition;
+}
+
+void MWMechanics::NpcStats::setDisposition(int disposition)
+{
+    mDisposition = disposition;
+}
+
 bool MWMechanics::NpcStats::getMovementFlag (Flag flag) const
 {
     return mMovementFlags & flag;
diff --git a/apps/openmw/mwmechanics/npcstats.hpp b/apps/openmw/mwmechanics/npcstats.hpp
index 66f20a676f..35af4afa02 100644
--- a/apps/openmw/mwmechanics/npcstats.hpp
+++ b/apps/openmw/mwmechanics/npcstats.hpp
@@ -43,6 +43,7 @@ namespace MWMechanics
             std::map<std::string, int> mFactionRank;
 
             DrawState_ mDrawState;
+            int mDisposition;
             unsigned int mMovementFlags;
             Stat<float> mSkill[27];
             int mBounty;
@@ -61,6 +62,10 @@ namespace MWMechanics
 
             void setDrawState (DrawState_ state);
 
+            int getDisposition() const;
+
+            void setDisposition(int disposition);
+
             bool getMovementFlag (Flag flag) const;
 
             void setMovementFlag (Flag flag, bool state);