There are thousands of books, music and other works that are in the public domain of the United States, meaning, they are available to anyone for free as they their copyright no long applies.
Copyright laws have changed frequently over the years; here are some examples. Works created prior to 1923 are in the public domain. Works copyrighted between 1923 through 1963 expire 95 years after publication date of the copyright was renewed. For works created after 2002, they become part of the public domain 70 years after the death of the author. More details at copyright.cornell.edu/resources/publicdomain.cfm.
That said loyalbooks.com provides over 7,000 books free to the public that have become part of the public domain, both in eBook and audio book format. Books like The Adventures of Huckleberry Finn, Moby Dick, Great Expectations, Treasure Island, The Odyssey, Gulliver's Travels, War and Peace, The Curious Case of Benjamin Button, Bill Nye's Comic History of the United States and so many more.
The site also has books in foreign languages, including Chinese, French, German, Italian, Japanese and others. Visit www.loyalbooks.com to access books immediately and without registration requirements.