Change making for evil dudes

[Swish2]

Aside from "mining" the vendor, as in buying all stock of visible items to see what else appears... there's nothing you can do, and this is expensive a lot of the time.

Best bet is to find a local gnome to trade with who's running to the bank or can buy you some food/water with the copper/silver you've got ^^

(or try the Butcherblock druid ring, but likely that's the same scenario)