1) Virtual economy 
Monopoly money is a type of play money used in the board game Monopoly. It is different from most currencies, including the American currency or British currency upon which it is based, in that it is smaller, one-sided, and comes in different colors. ==Format== There exist many variations of Monopoly, with many types of money representing various ...
Monopoly money is British slang for a vast, unobtainable sum of money.