Where is the cheapest place to purchase college textbooks and supplies FAST?

I need to know because my loan isn't processed yet and I need to still purchase books but want to watch my spending as well as gettign them shipped fast bc my instructors are already using them on the second day of cles. Damn Stafford Loan processing takes forever when it's yoru first time having to borrow! Maybe it's just the crazy school I am attending here in Atlanta! GEEZ!