"For thousands of qualifying books, your past, present, and future print-edition purchases" is difficult to parse. It reads like list(4) instead of statement, list(3). It sounds as if you don't need to purchase print editions to get certain qualifying books cheaply on kindle.

I'm glad you found it clear and straightforward but a glance through the comments here shows that several other people were also confused.

When you buy a qualifying print-edition book from Amazon you can get the Kindle edition on Matchbook for $2.99, $1.99, $0.99, or free.*

* Applies to past, present, and future purchases.

Well, how do I find out which books are eligible, and at what price? Is it available now or coming soon? How do I sign up? Do the books have to be ones I bought through Amazon, or can I like take a picture or something of a book I got at a garage sale?

With Kindle MatchBook, you'll be offered discounted or free e-books to go along with books you already own through Amazon. Check out AutoRip, our similar service for Music!

"Get the e-book along with the physical book for a small fee"

Its OK I suppose. The "future print edition" part was vaguely confusing to me given that I'm bombarded with offers for pre-orders regularly. Depending on your initial interpretation it can be either clear or somewhat confusing.