I have mentioned in the past that Amazon has a ton of free Kindle books available. I don't have a Kindle, but you don't need one either, for these free books!
You can download the Kindle for PC for free from here.
When I got an Android phone I got the free Kindle app, so all my books from my computer automatically synced to my phone.
Check out this list that BargainBriana put together of all the free ones available right now! Remember, these prices can change any minute so check before you purchase!