I used to think that the change from giving money of greater value than the total purchase was a profit for the buyer.
A childhood belief about going shopping

others believed things like this
- When I was little I used to believe that there was a man sitting inside ATM machines giving you your money.— Kazza
- I used to think when we moved, it was because we were exchanging our house with the buyer's... — Pat
- I thought you could make a profit out of profiteroles.Anon
- that people in shops gave you 'change' if you didn't quite have enough money to pay.— suzy
- I used to believe that coin change could turn into actual paper money if you left it alone for a long time. — Marcus O
- When I was a little kid I used to believe that tissue paper was money and that you could have a box of money.Anon