The trading/bartering screen is confusing.

[linusno]

first there should be a warning that you are going to sell all your stuff for zero gold if you don't manually add gold from the trader in batering mode. It's embarrassing how many times I gave away my stuff before I realised I did not get any gold in return.

Then there should be an indication on what the actual price the trader wants for an item is. If you hover over the item there is a number in the left bottom corner, but as far as i can tell there is no correlation to what the actual price is.