No matter what kind of device you own or are reading this on --- phone, tablet, or browser --- there are thousands of places offering you literally millions of no-strings, free ebooks, audiobooks, movies, and music.
You probably already know that your local public library likely offers myriad ebooks and audiobooks (fiction, non-fiction, reference...) plus streaming movies and music, for free. Smaller libraries often are linked electronically to the catalogs of larger libraries in nearby cities or at schools and universities. Public libraries tend to have current offerings, too; e-media often shows up at libraries at about the same time it shows up in commercial locations.
One of the most popular free apps for borrowing books from a public library is Overdrive (http://app.overdrive.com/); one of the most popular apps for borrowing movies and music from a public library is Hoopla (https://www.hoopladigital.com/). Your local library's home page will clue you in to what works best with their collections.
Project Gutenberg (https://www.gutenberg.org/) focuses mostly on public domain books, which usually means older, classic literature. At last count, Project Gurengerg alone has almost 50,000 titles on offer, all free.
The folks at OpenCulture have curated a list of some 700 free ebooks and audiobooks offered by a variety of sources.
Free-ebooks (http://www.free-ebooks.net/) offers two levels of membership: A free account gets you up to 5 ebooks a month; a paid account gets you unlimited ebooks, and audiobooks, too.
Free Book Spot (http://www.freebookspot.es/) and eBooks-share (http://www.ebooks-share.net/) are related sites that tend to focus on newer, up-and-coming authors who may not have landed on the bestseller lists yet.
An article at hongkiat lists their choice for the 20 Best Websites To Download Free EBooks.
And if you need still more, a Google search for free ebooks turns up over 84 million hits.
In short: there's never a reason to be without something to read, watch, or listen to, on whatever electronic device you own.