Very sorry that you are mistaken/misinformed.
Here is what US Bank says about selling foreign currency.
Link Here
How do I exchange or sell my foreign currency?
Visit a U.S. Bank branch and a banker will help you through the process. We encourage you to make an appointment to allow time for questions and processing.
Full order returns within seven (7) days of purchase:
We will buy back the currency at the same exchange rate used for purchase.
A $10 return fee applies.
Full or partial returns after seven (7) days of purchase:
We'll process your return at the current day's exchange rate.
A $10 fee applies to returns of $250 USD or less.
So , a bank will not pay you 80 cents per euro to buy it back.
Today's rate is $1.06 per euro. For 200 euros, that would be $212 US dollars minus the $10 fee. Making it $202 US you'd get for 200 euros or 202/200 = $1.01 US per euro. A long way from 80 cents.