Kindle Unlimited is Amazon's subscription service catering to the avid reader. For a monthly cost of $9.99 / £7.99 / AU$13.99, you get access to millions of titles – including some audiobook versions of the ebooks – and you're allowed to 'borrow' no more than 10 at a time. That means you can't have more than 20 'saved' titles in total in your library. Whether it's worth the monthly subscription will depend on how much you read and what you like to read. There are some popular titles and authors in the catalog but it can be a little skewed towards romance and self-published content. This can be great for someone who keeps needing new things to read all the time, but if you're after something specific, Kindle Unlimited may not be for you. Find out more in our in-depth Kindle Unlimited review.