[Bug]: The Goldface overcharges and sometimes undercharges you at random.

### Checks

- [X] I have searched the bug with a few keywords, and I confirm this bug was not yet reported.

### Location

RogueTown

### Describe the issue

Everytime i try to buy something from the goldface i must cross my fingers, that the price which stands next to the Item is a right price. i tried buying the scrying orb, which cost around 400. missclicked and buyed the ring (which also cost around 400). No trouble. i have 200 in my account and 200 in the goldface to pay the right item again. OH! The Goldface charged me 600 for an item which is listed for 400. its terrible to play merchant, when the goldface plays against you.

### How to reproduce

Buy stuff from the goldface multiple times

### Round ID

every round. bugged me very much during Xan117-23.37.45

### Staff ckey

_No response_

No file or test is named. Reproduce the Goldface purchase flow in RogueTown with the scrying orb and ring, comparing displayed and charged prices across repeated purchases; done means charges consistently match the listed prices.

Written by the indexing model from the issue text.