How much change would you give a customer who gives you a 3 dollar bill for a $2.50 purchase?

How much change would you give a customer who gives you a 3 dollar bill for a $2.50 purchase?

You're a cashier in a store. A customer is buying a small trinket with a price of $2.50 on it. They hand you a 3 dollar bill for payment. What do you give them as change?

This question is prompted by @exitseven...

Can you "make change" ?

Updates
11 mo
There is no 3 dollar bill, at least not a legal one. If you look carefully at the image, you'll notice that it's a "TWE DOLLAR BILL", with signatures by "A. Phoneybill" (left) and "U. Canteashit" (right).

Many of you got it right. Don't give any change and call security or the cops.
How much change would you give a customer who gives you a 3 dollar bill for a $2.50 purchase?
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