The phrase "monopoly money" refers to play money used in the board game Monopoly. It is used to describe something that is not real or valuable in a serious or important situation.
Sentences with «monopoly money»
But there were still too many moments when the money felt like monopoly money. (theeverygirl.com)
He was never 30 mil... why do you insist on blowing up every player's price, do you think this is just monopoly money? (justarsenal.com)
There are 30 + such monopoly money deals under discussion at present. (nystateofpolitics.com)