If the IRS asks you to prove those education expenses, then you'll need something showing that you paid them.
It doesn't necessarily have to be an actual receipt from a store; it could be a cancelled check, a college account statement printout (showing bookstore amounts), a credit card (or bank) statement showing the place & amount of purchase (coupled with some breakdown of purchases), or an invoice along with any of these things.
You'll need something to show that you actually paid the amounts claimed.
