However, it's easy to swap these titles out so you'll never get stuck paying for something you don't ultimately enjoy. It's worth remembering that you are allowed to 'borrow' a maximum of 10 titles at a time and save 20 in total in your library.
However, it's not included in Amazon Prime. Amazon Kindle Unlimited includes unrestricted access to a whole library of ebooks and more, which means you're covered for all your reading needs whatever you feel like getting stuck into.