The two books motivating this blog are available for free online and can be bought in hard copy. Apparently, they are selling well, which proves that one can make money from providing free books. Following this model (possibly independently developed, we do not know as this model was not patented), Flat World Knowledge
is now starting to offer textbooks. Print copies are less expensive than the "traditional" outlets, and pdfs can be downloaded for free.
The catalog is small so far and concentrated on Economics and Business, but there are some good names. I find it quite interesting that Business books are listed, as I found faculty in business schools generally very skeptical that one can provide a good service at no cost.
If you are unable to get free textbooks but need cheap college books
, I recommend visiting CheapestTextbooks.com.