Whether your device is Apple, Kindle, Android, Windows or whatever else is available out there, you can get free books.
There are a gazillion resources out there for free books, but I am only interested in telling you about this one, BookBub. I've been using it for quite a few months now and am well pleased with it. I have shared it with friends and they too are reporting positive reviews, and none of us have encountered any problems.
So all you do is go to BookBub.com and register, when you register you indicate how you read your ebooks and it sends you a daily selection of at least 1, but quite often more books from which to select. Occasionally there will be selections for a very low price, but if you don't want them don't take them.
BookBub is also available on facebook, just search for them, Like them, and selections will start to appear on your Wall.
other free ebook resources
heck just google free ebooks and just see what all comes up!