Anyone who is a student should know that most of the big publishers e.g. Springer, Cambridge Uni. Press, etc have extensive online libraries that your university probably subscribes to. You can go there and download complete books, many of which would be extremely expensive to buy otherwise. A lot of it is academic and dry, but occasionally there are some gems. It was fun to sift through random topics that I had no idea about (like forensic pathology) and build up a small eBook library. Best of all it's within your right as a student to do it (your uni pays thousands for these subscriptions), so exploit it while you can.
Most of the time you have to download chapters separately, but I did write a little script that would authenticate with Shibboleth, pull the whole book and combine the PDFs. There was no DRM either, just a watermark with your IP or university details to discourage sharing.