Right now, Amazon is running a  special trial offer for Kindle Unlimited on the Kindle Books main page. The offer allows you to try the service for two months for only 99 cents.

The fine print:

• This offer is only open to new subscribers. Existing Kindle Unlimited subscribers are NOT eligible.
• The offer must be redeemed before   March, 11 2018.
• The cost is $0.99 for the first two months and $9.99/month after that until you cancel.

With Kindle Unlimited, you may read Kindle books and listen to Audible audiobooks from a designated list of titles an unlimited number of times for so long as you are a member of the program. You may borrow 10 titles at a time.

The service features over a million titles, revolving monthly magazine selections, and books with Audible narration that can be read on any device or app.

You can see the regular 30 day free trial Kindle Unlimited offer and plans here.