Almost everything work related that you'll need to buy as a graduate student, whether it be textbooks, lab equipment, or office equipment, is available on campus. There are also a wide range of machine shop, photocopying, computing, and consulting services available on campus. This is a summary of some of the most common places that grad students use. You should also ask your advisor and other grad students in your research group if there is a place they prefer you to use. One advantage to using on-campus stores and services is that you can almost always charge expenses directly to a research charge account (check out Section 3.4.1 for more information on this). However, if you're spending your own money, there may be places around Ithaca or on the internet that charge less.