Another idea not sure if its mentioned but maybe make an option for co-op game so you can have a friend to help in the shop and allow players to work together.
It could be an idea but not sure. what if at some point in the game the king orders something from the black smith and depending on how u make it (rarity of items) the king pays extra but not too much. for example: if he wants a sword u cn make it with any ingot and any rarity grip and handguard.