Personaly i like this mechanique ...
If you are selling all your loot to vendor, its nice to have a little extra something to get from him, when he cant afford give you any more money.
Also i think gold is quite fine ...
If you can make anyone like you by giving him a hammer ... it makes completely sence that you can get the same result by giving him money for that hammer.
It maybe should be just adjusted so it would not be so easily exploitable ...
Or implement there some maximal discount from attitude ...
The point is . . . he needs a hammer. He's out in the wilderness and can't work without one. All the gold in the world isn't going to make a hammer magically appear so he can start crafting/repairing weapons for the Tieflings to defend themselves with.
