piece of change
1. Any sum of money, usually specified by an adjective. That's a pretty big piece of change to drop on a used car! I've been putting away little bits of money for a few years, and now I have a nice little piece of change saved up for a trip to Japan.
2. A coin. Legend has it that anyone who drops a piece of change into this well will have any wish their heart desires granted.
piece of change
A sum of money, especially a considerable amount, as in That car is worth a piece of change. [Slang; early 1900s]