Have you heard of Project Gutenberg?
Project Gutenberg began in 1971, the first e-text collection on the Internet. It’s an all-volunteer effort to digitize, archive, and make cultural works accessible to everyone for free. These are e-books (and audiobooks), but you don’t need an e-reader to use them; just a computer. You can read them online, or download them.
There are over 40,000 works available, mostly those in the public domain (their copyright has expired): all the classics. You can volunteer, too, to digitize or record books.
Go to Project Gutenberg to read more, and have a look around for yourself!