Amazon.com on Friday introduced Kindle Unlimited - a new unlimited subscription service which allows consumers to read Kindle books and listen to Audible audiobooks, for $9.99 a month. Subscribers to the Kindle Unlimited service can read the e-books on Amazon's Kindle reader or on any device that supports the Kindle app.

Customers can choose from books including "The Hunger Games," "Life of Pi," and "Diary of a Wimpy Kid."