gutenberg.org has loads of old classic books on it for free. Pretty much everything before the 30s i think. 36,000 books anyway.
This one is a beast. It's from by Jack London from 1910 and about a guy in a straitjacket in solitary confinement for murder. He has these journeys back in time to a variety of times and places. Really recommend this one.
http://www.gutenberg.org/ebooks/1162