Over at Greyhart Press, there’s a promotion called Read! Review! Repeat! Basically, if you’re one of the first 100 people to post a review of a Greyhart Press book on Amazon, Goodreads or similar, you can claim your next Greyhart eBook for free.
Not all of my books are published through Greyhart Press, but my new time travel series (The Reality War) is.
If you’re cunning, you might pick up one of the free Greyhart Press titles and review your way through as many books as you like, without paying for any of them.