Aron, from Ultima Underworld II
Aron used many words to impress the Avatar while also praising his selection of goods for the adventurer. However, once the Avatar saw the selection, it became clear that Aron was mostly hot air, as his goods were the cheapest, mostly useless stuff (torches and apples for example). Therefore it didn't hurt the Avatar to not trade with Aron at all.
He later dies, if the Avatar crashes the keep.