Child’s Play
Some kids in town came up with a pretty impressive hustle.
Canada was a year or two from retiring the penny and there was a shortage so banks had a deal saying if you brought in $10 worth of rolled pennies, they would give you $12 cash. These guys (they were around 10 years old) took in all their pennies and made the $2 per $10. Then went to another bank and bought $12 worth of pennies, went to the next bank and sold them back. Rinse and repeat, making 20% per transaction until bank staff (we only have half a dozen banks in town) figured out the hustle.
Story credit: Reddit / Norse_of_60