Unexpected money that one obtains in a manner that differs from one's usual sources of income.
2004, Dan Benson, 12 Stupid Mistakes People Make with Their Money, page 64:
You can slice some girth from your debt load with a couple of big lump-sum payments, courtesy of any found money that comes along.
2010, Gary Belsky, Thomas Gilovich, Why Smart People Make Big Money Mistakes and How to Correct Them:
Note, though, that the rules of mental accounting are flexible—people are complicated. Sometimes they will categorize tax refunds, especially when they are small, as found money—and spend it accordingly.
2013, Raymar Rodriguez, The Little Red Book of Financial Happiness: Life After Prison, page 62:
My father's attitude toward his hoard was that it was almost found money. The money had trickled in little by little, and he never felt the sacrifice of saving.
Used other than figuratively or idiomatically: seefound, money. Money that one finds.
