An alternative would be a traditional flatbed scanner.

While not ideal for catching up on a backlog of unscanned documents, it isn't bad for scanning current documents. They can be bought for anywhere between $30-70.

As another thing to consider for non sensitive documents (things like course notes or the like) would be do find a copy machine on campus that can scan multiple pages in a row. The ones at my school have the option to email pdfs to you rather than print. It might be a good (free) way to scan many documents at once if you can find one.