Amazon's Kindle MatchBook service officially launched on Tuesday morning. As we learned when Amazon announced it, MatchBook lets you purchase an eBook version of a physical book you've purchased through Amazon. Instead of charging the typical price, usually around $9.99, Amazon will provide you with a digital copy for free, $0.99, $1.99 or $2.99 at the most.

The Kindle versions of any book can be read on any machine with Kindle Reading App software on it, which includes computers, iPads, Android tablets, smartphones, Kindles and more. To get started, simply head to Amazon's site (in the source link below) and then log-in and choose see which books you've purchased qualify for a low-cost digital edition.

I've purchased dozens of books through Amazon, but since I typically buy used copies from Amazon's third-party partners, I don't have any that qualify for a digital version. That's sort of the catch: it only applies to books you've purchased brand new and direct from Amazon. On the other hand, that's a compelling reason to buy future books from Amazon instead of another bookstore.