One thing you need to understand first, is that most of these free books will come in the form of ARCs. An ARC is an Advanced Reader Copy given to promoters and reviewers by authors and publishing companies, usually 6-3 months before the book's release. ARCs usually come in the form of a digital file that you can download to your Ereader. Once in a while, you may score a print copy, but for obvious reasons, digital is usually the way to go with publishers. NOTE: It is illegal to sell or trade ARCs.
Start a Blog
Or in other words, become a reviewer. Even if you only average one book a month, tell the world what you think about it. Authors seeking to promote their new book WILL find you and and offer you an ARC. In no time, you'll have requests piled up in your in-box. Free books for life!
Book Review Blogs
As I stated before, it is illegal to sell ARCs, but book review blogs will often giveaway a print ARC in a contest. It would definitely be beneficial to follow a few and keep up with their giveaways. One I've noticed that gives away free print copies all the time is Aesta's Book Blog.
This website is fantastic, because after you make a profile, you can actually request which ARCs you want. They feature both major publishers and small press. Whether or not you get approved for a requested ARC is based on solely on the publisher of the book. The major ones will probably check out your blog and see what kind of audience you bring in with your reviews. If you want to read new books before you they hit the shelves, go make a profile right now!
Become a Beta Reader
This is another easy way to get a hold of books before they are released. Several publishers, especially small press, will post on their websites that they are looking for beta readers. Think of a beta reader as someone who tests out the book before it is published. You can give the author feedback and know that your opinion was heard. If your favorite author or publisher doesn't have a Beta Reader click, email them and tell them you'd love an ARC in exchange for posting reviews. Most will probably go for it, especially if the book comes after the first in a series. One publisher with fabulous authors that is always looking for advanced reviews is Gryfyn Publishing. They've never turned me away.
Authors, whether independently published or not, are always doing as much promotional work as their publishing team, if not more. One way they do this is by doing giveaways on their blogs, Facebook, Twitter, Goodreads, what have you. If you have a favorite author you'd be stupid not to follow them on social media. Not only will you have the first inside look to your favorite stories, but you'll have a chance to win autographed books! Personally, I have yet to win anything. But I'm crossing my fingers because I know my number is coming soon!
Online Release Parties
After you start following your favorite authors, you might get invited to a few online release parties. This is a great way to win free books. They usually happen for a few hours the day the book is released and there are several chances to win print, ebooks, and gift cards from several authors who have teamed up. For contest entries, you will usually have to "like" that author's facebook page, sign up for their newsletter, or add one of their books on Goodreads. The book I'm currently reading is one that I won at a release party.
Kindle Free Store
Now the books you'll find for free in the Kindle Store might not necessarily be new, but that's never really bothered me, since I book I haven't read is essentially a new book. This is the way I score the majority of my free books. There are stacks of them on my kindle shelf since I find intriguing books so often that I can't catch up on my reading list. Sound familiar? Its common for publishers and indie authors to make the first book in a series permanently free. But be careful, this free sample is a marketing ploy to get you to pay for the rest of the series. And it works! I found my favorite romantic fantasy series from a freebie. I highly recommend it.
Free Ebook Websites
These websites are devoted to notifying readers free promotions and deeply discounted sales on ebooks. Even bestsellers. You can check the websites at your leisure or sign up for their mailing list. Most are customized to your preferences and how often you wish to receive notifications. Which is nice, since no one wants their in-boxes stuffed with spam. Some good ones are Addicted To Ebooks, Ebooks Habit, Goodkindles, and Indie Book Of The Day . The most popular one used by major publishers is BookBub
Authors, you can also add your books and advertise on these sites. Most are pretty affordable and have gotten me results.
Support Your Library
Don't forget, you have access to free books right around the corner! Even new releases. Libraries have budgets to buy new books and their first priority are the top bestsellers. They are the most underutilized resource in our communities. If you have a reading addiction and also a budgeting problem, you probably already know this. But honestly in our digital world libraries seem to be the best kept secret.
Please Leave Reviews
One thing to keep in mind, is that if you personally receive and ARC from an author or publisher, the courteous thing to do is to add that book to the top of your TBR list and then leave a review when you're finished. Doesn't have to long, doesn't even have to be flattering. Just an honest rating on Amazon or Goodreads means the world to an author. One of the biggest things people look for when they buy a book on Amazon is how many reviews it has. The more reviews a book has, the more people have read it. Lots of readers means there must be something to it, right? Your opinion and support are extremely important to the author community and keep the book world turning. Without readers, there is no reason to write.