diff --git a/apps/openmw/mwgui/container.cpp b/apps/openmw/mwgui/container.cpp
index 14a500b69..710e30b74 100644
--- a/apps/openmw/mwgui/container.cpp
+++ b/apps/openmw/mwgui/container.cpp
@@ -186,11 +186,13 @@ void ContainerBase::sellAlreadyBoughtItem(MyGUI::Widget* _sender, int count)
     if (isInventory())
     {
         MWBase::Environment::get().getWindowManager()->getTradeWindow()->addItem(object, count);
+        MWBase::Environment::get().getWindowManager()->getTradeWindow()->buyFromNpc(object, count);
         MWBase::Environment::get().getWindowManager()->getTradeWindow()->drawItems();
     }
     else
     {
         MWBase::Environment::get().getWindowManager()->getInventoryWindow()->addItem(object, count);
+        MWBase::Environment::get().getWindowManager()->getTradeWindow()->sellToNpc(object, count);
         MWBase::Environment::get().getWindowManager()->getInventoryWindow()->drawItems();
     }
 
@@ -199,14 +201,18 @@ void ContainerBase::sellAlreadyBoughtItem(MyGUI::Widget* _sender, int count)
 
 void ContainerBase::sellItem(MyGUI::Widget* _sender, int count)
 {
+    MWWorld::Ptr object = *mSelectedItem->getUserData<MWWorld::Ptr>();
+
     if (isInventory())
     {
-        MWBase::Environment::get().getWindowManager()->getTradeWindow()->addBarteredItem(*mSelectedItem->getUserData<MWWorld::Ptr>(), count);
+        MWBase::Environment::get().getWindowManager()->getTradeWindow()->addBarteredItem(object, count);
+        MWBase::Environment::get().getWindowManager()->getTradeWindow()->buyFromNpc(object, count);
         MWBase::Environment::get().getWindowManager()->getTradeWindow()->drawItems();
     }
     else
     {
-        MWBase::Environment::get().getWindowManager()->getInventoryWindow()->addBarteredItem(*mSelectedItem->getUserData<MWWorld::Ptr>(), count);
+        MWBase::Environment::get().getWindowManager()->getInventoryWindow()->addBarteredItem(object, count);
+        MWBase::Environment::get().getWindowManager()->getTradeWindow()->sellToNpc(object, count);
         MWBase::Environment::get().getWindowManager()->getInventoryWindow()->drawItems();
     }
 
diff --git a/apps/openmw/mwgui/container.hpp b/apps/openmw/mwgui/container.hpp
index d300f4497..66cac82ce 100644
--- a/apps/openmw/mwgui/container.hpp
+++ b/apps/openmw/mwgui/container.hpp
@@ -74,6 +74,7 @@ namespace MWGui
         void returnBoughtItems(MWWorld::ContainerStore& store); ///< return bought items into the specified ContainerStore
 
         MWWorld::ContainerStore& getContainerStore();
+        MWWorld::ContainerStore& getBoughtItems() { return mBoughtItems; }
 
         void openContainer(MWWorld::Ptr container);
         void setFilter(Filter filter); ///< set category filter
diff --git a/apps/openmw/mwgui/tradewindow.cpp b/apps/openmw/mwgui/tradewindow.cpp
index fb70e0045..06e91d787 100644
--- a/apps/openmw/mwgui/tradewindow.cpp
+++ b/apps/openmw/mwgui/tradewindow.cpp
@@ -145,6 +145,64 @@ namespace MWGui
 
     void TradeWindow::onOfferButtonClicked(MyGUI::Widget* _sender)
     {
+        // were there any items traded at all?
+        MWWorld::ContainerStore& playerBought = mWindowManager.getInventoryWindow()->getBoughtItems();
+        MWWorld::ContainerStore& merchantBought = getBoughtItems();
+
+        bool traded=false;
+        for (MWWorld::ContainerStoreIterator it = playerBought.begin();
+                it != playerBought.end(); ++it)
+        {
+            if (it->getRefData().getCount() > 0)
+                traded = true;
+        }
+        for (MWWorld::ContainerStoreIterator it = merchantBought.begin();
+                it != merchantBought.end(); ++it)
+        {
+            if (it->getRefData().getCount() > 0)
+                traded = true;
+        }
+        if (!traded)
+        {
+            // user notification
+            MWBase::Environment::get().getWindowManager()->
+                messageBox(MWBase::Environment::get().getWorld()->getStore().gameSettings.search("sBarterDialog11")->str, std::vector<std::string>());
+            return;
+        }
+
+        // check if the player can afford this
+        if (mCurrentBalance < 0 && mWindowManager.getInventoryWindow()->getPlayerGold() < std::abs(mCurrentBalance))
+        {
+            // user notification
+            MWBase::Environment::get().getWindowManager()->
+                messageBox(MWBase::Environment::get().getWorld()->getStore().gameSettings.search("sBarterDialog1")->str, std::vector<std::string>());
+            return;
+        }
+
+        // check if the merchant can afford this
+        int merchantgold;
+        if (mContainer.getTypeName() == typeid(ESM::NPC).name())
+        {
+            ESMS::LiveCellRef<ESM::NPC, MWWorld::RefData>* ref = mContainer.get<ESM::NPC>();
+            if (ref->base->npdt52.gold == -10)
+                merchantgold = ref->base->npdt12.gold;
+            else
+                merchantgold = ref->base->npdt52.gold;
+        }
+        else // ESM::Creature
+        {
+            ESMS::LiveCellRef<ESM::Creature, MWWorld::RefData>* ref = mContainer.get<ESM::Creature>();
+            merchantgold = ref->base->data.gold;
+        }
+        if (mCurrentBalance > 0 && merchantgold < mCurrentBalance)
+        {
+            // user notification
+            MWBase::Environment::get().getWindowManager()->
+                messageBox(MWBase::Environment::get().getWorld()->getStore().gameSettings.search("sBarterDialog2")->str, std::vector<std::string>());
+            return;
+        }
+
+        // success! make the item transfer.
         transferBoughtItems();
         mWindowManager.getInventoryWindow()->transferBoughtItems();
 
@@ -276,4 +334,22 @@ namespace MWGui
 
         return items;
     }
+
+    void TradeWindow::sellToNpc(MWWorld::Ptr item, int count)
+    {
+        /// \todo price adjustment depending on merchantile skill
+
+        mCurrentBalance -= MWWorld::Class::get(item).getValue(item) * count;
+
+        updateLabels();
+    }
+
+    void TradeWindow::buyFromNpc(MWWorld::Ptr item, int count)
+    {
+        /// \todo price adjustment depending on merchantile skill
+
+        mCurrentBalance += MWWorld::Class::get(item).getValue(item) * count;
+
+        updateLabels();
+    }
 }
diff --git a/apps/openmw/mwgui/tradewindow.hpp b/apps/openmw/mwgui/tradewindow.hpp
index b96abc7e2..8da96d37e 100644
--- a/apps/openmw/mwgui/tradewindow.hpp
+++ b/apps/openmw/mwgui/tradewindow.hpp
@@ -27,6 +27,9 @@ namespace MWGui
 
             void startTrade(MWWorld::Ptr actor);
 
+            void sellToNpc(MWWorld::Ptr item, int count); ///< only used for adjusting the gold balance
+            void buyFromNpc(MWWorld::Ptr item, int count); ///< only used for adjusting the gold balance
+
             bool npcAcceptsItem(MWWorld::Ptr item);
 
         protected:
diff --git a/apps/openmw/mwworld/containerstore.hpp b/apps/openmw/mwworld/containerstore.hpp
index 96c97415d..f850b01fa 100644
--- a/apps/openmw/mwworld/containerstore.hpp
+++ b/apps/openmw/mwworld/containerstore.hpp
@@ -74,7 +74,7 @@ namespace MWWorld
             /// \attention Do not add items to an existing stack by increasing the count instead of
             /// calling this function!
             ///
-            /// @return if stacking happened, return iterator to the item that was stacked against, otherwise end() iterator
+            /// @return if stacking happened, return iterator to the item that was stacked against, otherwise iterator to the newly inserted item.
 
         protected:
             ContainerStoreIterator addImpl (const Ptr& ptr);