After William T. Riker won more latinum at the dabo table in Quark's Bar than Quark could pay, Quark gave Riker vouchers worth twelve bars of platinum vouchers which were only redeemable at the bar. In 2370, Riker offered them back to Quark in exchange for information about Lursa and B'Etor, only to be told afterwards that Quark had voided them while they had been talking. (TNG: "Firstborn")
It is unclear whether the type of voucher referred to in "Mudd's Passion" exists at all, or if the entire concept of their existence was faked. In the novelization of that episode (as published in Star Trek Log 3), these are referred to as "credit vouchers" and Mudd claims that he apparently gave the miners an Andalusian pleasure slave in exchange for the fabricated vouchers, although the miners were annoyed to discover it was actually a pneumatic automaton.