"He runs Gold exchange in the Wizard Town. It used to be a shop called 'Your Darkness' but it was replaced with Gold exchange, probably because Your Darkness sold evil things"
Percival Bendrist II to his friends

Gold Exchange was a shop in the Wizard Town owned by Timothy Woolustuc. This was where wizards can exchange Gold coins for objects. This shop was the most successful money attempt of Timothy.

It used to be a shop called Your Darkness which sold evil objects, presumably the reason it was changed.