The MIT Coop is a great bookstore, although it is a bit expensive. On the main floor, they sell all kinds of books, snacks and MIT apparel and memorabelia. Downstairs, they sell stationary and other paper goods. The location of the store is great - they have lots of windows, so if you are waiting for a bus, you can browse some of the books while you are waiting and keep and eye on the bus stop! It is also attached to the Kendall Square food court and right next to the T stop. It is worth a visit, especially if you are in the area!