Bitlit works with publishers to get you free or discounted access to digital copies of books you own in print: you use the free app (Android/Ios) to take a picture of the book’s copyright page with your name printed in ink, and the publisher unlocks a free or discounted ebook version. None of the Big Five publishers participate as yet, but indies like O’Reilly, Berrett-Koehler, Red Wheel Weiser, Other Press, Greystone, Coach House, Triumph, Angry Robot, Chicago Review, Dundurn, and PM Press (publishers of my book The Great Big Beautiful Tomorrow) are all in.
(Image: Bookshelf, David Orban, CC-BY)