Today only, Nov 30, 2015, Amazon is offering up to 40% off their Kindle Unlimited services as part of their Cyber Monday sale.

With the Kindle Unlimited subscription you can access hundreds of thousands of Kindle books and thousands of audiobooks with Whispersync for Voice. You can keep up to ten books at a time and there are no due dates. Read your Kindle Unlimited books on any Amazon device, or free Kindle reading app.