Mordax et al

The main currency used on Derse is the same as on Prospit and throughout the rest of the medium, Boondollars. They are also referred to as boonbucks or boonies, and the symbol for the currency is a longtailed uppercase B with two vertical lines through it. This standard currency allows for easy commerce between the planets of the medium, and is considered the official currency of the medium.

Boondollars, both coins and larger denominations are made of stamped porcelain ceramic of no intrinsic material worth. On Derse, physical boondollars are largely kept in bank vaults and transactions take place directly between individuals’ accounts, typically either directly on a tab when the shop and buyer are familiar, or with a paper check. 

Of course there are other, less official currencies which are used for less official business. Gold, poker chips, and stamps are also exchanged as money in under the table situations; criminal enterprises mostly.