A couple of years ago I built an app (PayMeMaybe) which uses this idea to settle small debts between friends: https://play.google.com/store/apps/details?id=app.

A couple of years ago I built an app (PayMeMaybe) which uses this idea to settle small debts between friends: https://play.google.com/store/apps/details?id=app.paymemaybe.paymemaybe https://play.google.com/store/apps/details?id=app.paymemaybe... Wasn't quite the break through success I suspected :)