A free or discounted ebook version of a printed book is something I have been saying on various forums in reply to several questions about ebook prices.
Since getting my Kindle in September I haven't bought a single ebook fron a main publisher as the prices are too high for my liking. I have bought quite a few from Indie authors on Amazon and have been more than happy with the price and content. I still buy a lot of paperback as they are always less expensive than the Kindle version (UK) and will continue to do so in the future unless either the prices drop or as mentioned a digital version is included with or available for a discounted price.
This is getting an all the more common practice when buying dvd's/Blu Rays as several I have bought have had a digital copy with them. This has allowed me to put the films on a Android device so I have the movie with me.