If your book is in KDP Select, you'll need to launch a "Free Book Promotion" or a "Kindle Countdown Deal" to get your ebook discounted on Amazon. To do so, first search Amazon for the book on your bookshelf. Each book has a "Promote and Advertise" button next to it. Click this button to send an invitation to anyone who visits the page that shows up when they click through from Google or another search engine. When you hit 100 invitations, Amazon stops sending emails and the promotion is over. There are two types of promotions: free days and free hours. With a free day, Amazon will put your book in the best possible light on its front page by giving it some attention. Readers will find out about your book project and may decide to buy it then and there. A free hour is exactly what it sounds like - one hour where your book is the only book available for sale on Amazon during that time period. If you have a popular book, a free hour can bring in a lot of sales. To start a promotional campaign, you'll need to sign up with Amazon Direct Publishing. This service is free for self-published authors looking to promote their books. You can also opt to pay $5,000 per year to be part of the KDP Select program. In this case, your book will be featured in the Amazon bookstore at any price point during the year long promotion period.