Textbooks
From booktorrent
Here are some of the better sites I've found for free (and/or cheap) textbooks in ebook formats.
Flat World Knowledge publishes lots of textbooks, and are rapidly expanding. They have a wide variety of disciplines including the bigest selection in the humanities and social sciences that I've found. That seems pretty rare, as most open textbook services cater to the natural sciences and business. They, of course, have a ton of those too. The texts are extremely readable, especially their introductions to various disciplines. You don't need any kind of account, they're free to read on a web browser, cost a little for a pdf, and cost a bit more to have the book bound and sent to you.
Flat World Knowledge
Bookboon also has a ton of textbooks for the hard sciences, IT, and business. They're free to download as a pdf, but you have to sign up for the "newsletter."
Bookboon
