The marketing jewels of KDP Select: Free Days and Kindle Countdown Deals. In exchange for giving Amazon exclusive rights to digital book sales, you get the opportunity to choose 7 days (might be 5 for Free Days) to discount your book and generate an influx of sales and reviews, hopefully moving you up in rankings enough to see a continued uplift in sales after your promo ends. My Kindle Countdown Deal went live today. Get Blood Toy for 99c, ends July 30 (US Only)! I will let you know how the deal works for those fellow authors who may be considering their own promo.