My thought was to use it, at least for a few years, as a promotion device. Give the books for free to anyone who buys the $400 machine. (Maybe you can have 1,000 books of your choice, so there’s not a lot of ‘waste’.) You’ll sell more machines that way, that’s for sure. And the people willing to buy the device are exactly the sort of people that an author like me wants to reach.
Or what if Amazon gave you a free Kindle e-book version of every physical book you’ve ever purchased from Amazon?