I'm currently in the process of getting rid of old textbooks and stocking up on required reading materials for a new college semester, and Amazon's timing couldn't have been anymore perfect. As you're textbook shopping in your college bookstore or elsewhere, Amazon Student let's you scan the barcode (which is super fast) to compare prices online. Alternatively, you scan the barcodes of books you already have so you can attempt to trade-in books for Amazon gift-cards (for future purchases on whatever you're looking to buy). Amazon Student does try to get students hooked into the Aamzon Student program (Amazon Prime) with a 6-month free membership, costing $39/year soon after.
The app integrates with other areas of Amazon as well: keep your Wish List handy (useful for all those Amazon gift-cards you'll be getting back), view Amazon Gold Box deals, and check out purchases right from the Amazon Student app. You can download it for free in the App Store.