Just a couple of years ago, I worked as a teller in a bank and people were coming in all the time wanting to trade in their foreign money. We had a $200 minimum and our fees made it undesireable on top of that. I always said I'd be happy to change the money personally at $1 for €1\£1. I know that at the time as an employee of the bank it would be frowned upon but have always thought it wouldn't be an issue outside of that employment.