Carnival Cash

fake money, aka tickets you "win" at carnivals to trade in for junk. No outside value. See Developer Hegemony, reward Theater.

Play Money is noticeably fake bills or coins intended to be used use as toy currency, especially for classroom instruction or as a marker in board games such as Monopoly, rather than currency in a legitimate exchange market. Play money coins and bills are collected widely. They can be found made from metals, cardboard or, more frequently today, plastic. For card games such as poker, casino tokens are commonly used instead. https://en.wikipedia.org/wiki/Play_money