Our bank currently doesn't charge a cash advance fee for non-customers. I proposed that we begin to charge $10 for each one and another employee said that they had been told it wasn't legal to charge for cash advances. I think it's legal, but wondered if anyone had anything to credit/discredit this. Thanks in advance!

Check your agreement with your card vendor. I believe that you might find out that the other employee is correct.

You are going to have to check your merchant agreement, but the fee most likely is prohibited as it would be a finance charge from the card issuer's standpoint.