One of the great benefits of the Internet is the growing access to copyright-free content. Science fiction classics lurk out there waiting to be discovered. Try one of these from Project Gutenberg and explore the site for more great, FREE, works.
Frankenstein; Or, The Modern Prometheus by Mary Wollstonecraft Shelley
A Connecticut Yankee in King Arthur’s Court by Mark Twain.
A Princess of Mars by Edgar Rice Burroughs
The Dunwich Horror by H. P. Lovecraft
The Strange Case of Dr. Jekyll and Mr. Hyde by Robert Louis Stevenson
The Hanging Stranger by Philip K. Dick