Something is (legally) wrong there. If the law requires sales tax for one company on the full price it should be the same for the other. The only thing I can think of is MAYBE because it was shipped to the store for you rather than being purchased directly from store stock at the AT&T store there is some "loophole" that allows them to get away with it. If I was Apple I'd "drop a dime" on AT&T with the revenuooors.