diff --git a/apps/openmw/mwgui/spellbuyingwindow.cpp b/apps/openmw/mwgui/spellbuyingwindow.cpp
index ece19cdc3..0e7925e28 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"
@@ -51,6 +52,7 @@ namespace MWGui
     {
         const ESM::Spell* spell = MWBase::Environment::get().getWorld()->getStore().spells.find(spellId);
         int price = spell->mData.mCost*MWBase::Environment::get().getWorld()->getStore().gameSettings.find("fSpellValueMult")->getFloat();
+        price = MWBase::Environment::get().getMechanicsManager()->barterOffer(mPtr,price,true);
 
         MyGUI::Button* toAdd =
             mSpellsView->createWidget<MyGUI::Button>(
diff --git a/apps/openmw/mwgui/spellcreationdialog.cpp b/apps/openmw/mwgui/spellcreationdialog.cpp
index 4ce056010..3abd4c31e 100644
--- a/apps/openmw/mwgui/spellcreationdialog.cpp
+++ b/apps/openmw/mwgui/spellcreationdialog.cpp
@@ -9,6 +9,7 @@
 #include "../mwbase/world.hpp"
 #include "../mwbase/environment.hpp"
 #include "../mwbase/soundmanager.hpp"
+#include "../mwbase/mechanicsmanager.hpp"
 
 #include "../mwworld/player.hpp"
 #include "../mwworld/class.hpp"
@@ -388,7 +389,7 @@ namespace MWGui
         float fSpellMakingValueMult = MWBase::Environment::get().getWorld()->getStore().gameSettings.find("fSpellMakingValueMult")->getFloat();
 
         /// \todo mercantile
-        int price = int(y) * fSpellMakingValueMult;
+        int price = MWBase::Environment::get().getMechanicsManager()->barterOffer(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 64710c279..cd66b46f5 100644
--- a/apps/openmw/mwgui/tradewindow.cpp
+++ b/apps/openmw/mwgui/tradewindow.cpp
@@ -6,6 +6,7 @@
 #include "../mwbase/world.hpp"
 #include "../mwbase/soundmanager.hpp"
 #include "../mwbase/windowmanager.hpp"
+#include "../mwbase/mechanicsmanager.hpp"
 
 #include "../mwworld/inventorystore.hpp"
 #include "../mwworld/manualref.hpp"
@@ -318,16 +319,17 @@ namespace MWGui
     {
         /// \todo price adjustment depending on merchantile skill
 
-        mCurrentBalance -= MWWorld::Class::get(item).getValue(item) * count;
+        mCurrentBalance -= MWWorld::Class::get(item).getValue(item) * count
+            + MWBase::Environment::get().getMechanicsManager()->barterOffer(mPtr, MWWorld::Class::get(item).getValue(item) * count,false);
 
         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 += MWWorld::Class::get(item).getValue(item) * count 
+            -  MWBase::Environment::get().getMechanicsManager()->barterOffer(mPtr, MWWorld::Class::get(item).getValue(item) * count,true);
 
         updateLabels();
     }
diff --git a/apps/openmw/mwgui/trainingwindow.cpp b/apps/openmw/mwgui/trainingwindow.cpp
index af61b3487..106df627e 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"
 
@@ -76,7 +77,7 @@ namespace MWGui
         for (int i=0; i<3; ++i)
         {
             /// \todo mercantile skill
-            int price = pcStats.getSkill (bestSkills[i].first).getBase() * MWBase::Environment::get().getWorld ()->getStore ().gameSettings.find("iTrainingMod")->getInt ();
+            int price = MWBase::Environment::get().getMechanicsManager()->barterOffer(mPtr,pcStats.getSkill (bestSkills[i].first).getBase() * MWBase::Environment::get().getWorld ()->getStore ().gameSettings.find("iTrainingMod")->getInt (),true);
 
             std::string skin = (price > mWindowManager.getInventoryWindow ()->getPlayerGold ()) ? "SandTextGreyedOut" : "SandTextButton";