Textbooks
You may have been able to get through 2 years of Cambridge without buying a book but unfortunately MIT courses are often very reliant on the course textbook.
Textbooks are almost always much cheaper in the UK than in America – sometimes by half the cost. A lot of MIT students, out of convenience, buy their textbooks from “The Coop”, a store with outlets around MIT and Harvard which sell textbooks, stationery and so on. This is not advisable, unless you badly need a textbook and are willing to pay a premium. A slightly cheaper bookstore is “Quantum Books”, just around the corner from the MIT COOP.
If you know what textbooks you need before you leave, then it is recommended to purchase your books from a UK high street retailer or an online bookseller such as amazon.co.uk. Some online retailers offer faster delivery than others so try various websites. It all depends on the book.
If you are already in the US, and willing to wait for overseas delivery or pay a marginal fee for faster delivery, then www.amazon.co.uk or www.addall.com are highly recommended. Addall.com searches for books at the lowest price at all the main online booksellers. The best price is almost always from a British based bookseller.
In conclusion, textbooks are much cheaper (even after delivery charges) if purchased through an online bookseller, rather than at a US bookstore. And if you must, having someone back in the UK purchase books from a bookstore and mailing them over could still be cheaper than buying in the US!