Wiktionary
n. Noticeably fake bills or coins intended for use as toy currency, especially with board games, rather than currency in a legitimate exchange market.
Wikipedia
Play Money (PM) 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.
Many online gambling sites offer "play money" games which can be played for freely-obtainable credits. These are usually offered alongside "real money" games. However, some sites also offer software that only offers play money games. Such software is usually downloadable from a parallel .net web address, which can then be advertised to the general public as a non-gambling website.
In 1997, the Winston Million (a cash prize award program on the NASCAR Winston Cup series) was won by Jeff Gordon at the Mountain Dew Southern 500. A Brinks truck led him around the victory lap, spewing bags of Winston play money.
Usage examples of "play money".
I'll add some money every month for play money, that will be cash.
Next to it lay a Monopoly board, its cover lost long ago, the pink and yellow and green rectangles of play money worn and creased from countless contests.
To the Service it's only play money, anyway, infinitely replenishible at will.
The money becomes play money, counters on a board, just something to move around, not really quantifiable in terms of anything with meaning to me.
When I was a child of four or five my brothers and I used great stacks of hundred-dollar bills as play money.
When I was a child of four or five my brothers and I used great stacks of hundred - dollar bills as play money.