[Suggestion]. study of trade items
1) AI buys little healing cans. With 4000 gold, it could allow banks to 5.4 per champion. I do not know how the AI is spending money (he can save on something else. Maybe he buys things. But in my healing banks are very important)
2) You can create a black market? For example there would be proved "things sell a player." To make these unique items could buy someone else. Make the zone of influence (like the one that the master quest. Priravnyvat but not the black market to the "wild lands"). Usually, the store sold a lot of different things (gathered from monsters). Or can it sell the most unique things (with a giant margin)