If you already have an Amazon account, You should utilize that information to log in into KDP, or you are able to produce a new account if you'd like to retain points individual. Royalty costs for self publishing with Amazon KDP vary from 35% to 70% for ebooks, according to https://maplepublishers.com/blog/how-to-start-your-career-as-a-self-publishing-author-with-maple-publishing/