This is 96% off the regular price you'd pay for three months of Kindle Unlimited.
Brad's Deals Editor Michael,
A $29.97 three-month Kindle Unlimited subscription drops to just $0.99 for new subscribers who sign up using an Amazon Prime account or a Prime free trial. A Kindle Unlimited subscription gives you access to over 1 million e-books, magazines, and Audible audiobooks, which you'll be able to access on any device using the Kindle app. This subscription will revert back to its $9.99 per-month price after the three-month promotional period, but you can cancel your subscription at anytime. There is no sales tax.