Not long ago I told you about Kindle MatchBook, which allows you to buy the Kindle edition of a qualifying physical book purchased from Amazon for $2.99 or less. Amazon offers a similar program for companion audiobook titles of qualifying Kindle purchases; it's called Whispersync for Voice.
Whispersync is the Amazon's technology that allows a reader to keep a Kindle book in sync across multiple devices. One could read the first chapter of a book on a Kindle, and then open the Kindle app on an iPad and read chapter two. Whispersync updates the farthest reading position across apps and devices.
Whispersync for Voice is really a two-part thing. The first part of it allows one to purchase an audiobook companion for qualifying Kindle books at a discount — in some cases a significant discount. The second part relates to sync. Once a person has both the Kindle book and the audiobook companion, one can read to a certain point in the book and then, within just a few moments, one could open the audiobook and continue the story, listening from where it was left off.
Kindle Fire owners can take advantage of something called "Immersion Reading," which allows them to read and listen to a book at the same time. The Fire highlights the words on the screen as the story is read aloud. Those of us with multiple devices can simulate immersion reading by taking advantage of Whispersync to sync the audio and the text for us. Press play, and then read along with the audio.
Amazon's pricing for the audiobook companions is a little more variable — and a little more expensive — than MatchBook titles, but it's still a great deal. The most expensive of my audiobook companions was $12.99, although most were in the range of $3.00 to $7.00, or so.
If you're planning on buying multiple editions of a book anyway, you can get more bang for your buck by buying the physical book from Amazon first, then the Kindle version, and then the audiobook companion.