Someone shared  a bunch of kindle books that are listed as free downloads at the moment.
http://www.amazon.com/s/?_encoding=UTF8&camp=1789&creative=9325&keywords=free%20kindle%20books&linkCode=ur2&qid=1385843209&rh=n:133140011,n:154606011,n:157325011,n:156699011,k:free%20kindle%20books,p_36:-0&rnid=133141011&tag=reafooout-20

example -