Not my find. Someone else posted the vendor gold cheat a couple of days ago :

- Go into a item category on the vendor and hover mouse over any item.
- Move mouse pointer to the left side and down to your characters name, without hovering over a new item on the right.
- Use 'S' and 'W' to move one item up and down in the list that's still on the right while keeping mouse pointer still at your name.
- After moving up and down once you should see the value of the item have lowered (I think to about 10%).
- Now hit 'E' to buy, and the vendor will just give you gold. You can just spam 'E' until the vendor is broke.

If you try hitting 'E' after the vendor is broke, you get a yes/no confirmation dialgue as expected. If you press yes you will still increase your speech skill. You can do this by just hammering 'E' over and over until your speech is 100.

I guess it only works on PC, but I don't play on console so I dunno if there's a way to move the cursor the same way there.

Kinda kills a big part of the game, but this is the cheat forum so enjoy it if you want to.