If you have anything you don't use anymore, and it's too large to sell online, Craigslist should be your go-to place to sell stuff. In college, you may want to sell all your furniture before moving home from school at the end of the year. Depending on what you own, a few $100 might be better than storing it or transporting it back with you. It's easy to setup a listing and sell anything on Craigslist.
Take advantage of your strong typing and computer skills. If you are a fast and accurate typist, if you are great at creating interesting presentations with sophisticated graphics, or if you excel at creating tables and graphs to represent data, you may be able to get paid to teach and help other students with their assignments and hone your own skills at the same time.