Enter Contests: These days there are so many bloggers and authors giving away books and now that there is The Book Depository has free shipping to a large number of countries, more international giveaways have opened up. Bloggers such as Kathy from I am a Reader, not a Writer hosts giveaway hops on a regular basis so definitely check those out.
Goodreads First Reads: If you have a goodreads account then you can go to the Goodreads first reads page and enter contests there. If you do win you aren’t obligated to review the book but it is a common courtesy If you do review the book on Goodreads once you review it. You can check out Goodreads First Reads program here.
Smashwords: This one is for ebooks. Most are published by self-published or indie authors and yes most you have to pay for, however, you can also find free books in any category that you like. I find that the free books are really good for giving you a taste of an authors work before deciding to purchase them. Plus, you can quite often find a few freebie gems on there.
Library: Most libraries offer membership for free and have a vast collection of books. I know that I like to use my library to get some good books out. Not only that, but it is a meeting place for other bookish people and you can peruse shelves for hours at a time if you want.