Coins in the Itreyan Republic come in three flavors - the least valuable being copper, the middle child, iron, and the fanciest, gold. In the words of the narrator, gold coins were about as rare as a likable tax collector, most plebs never laying eyes on one in their lives.
Itreyans coinage was originally referred to as "sovereigns", but given Itreya's penchant for brutally murdering their monarchs, the term has long since fallen out of vogue. Coppers were now sometimes referred to as "beggars", and irons as "priests", since those were the people usually found handling them with the most enthusiasm.
There was no commonly accepted slang for gold coins - anyone rich enough to possess them likely wasn't the sort who went in for nicknames. Or handled their own money.
The narrator refers to them as "tossers".