The most common description of Amazon’s Kindle Unlimited service is probably “Netflix for ebooks”. You pay a monthly subscription (£7.99), and can download to read as many eligible titles as you want. Prime offered a limited version of this as part of its benefits, but Unlimited- as the name suggests- opens it right up.
You can’t get every Kindle title through Unlimited. The major publisher’s lists may not be fully available, as they continue various disputes with Amazon. Indie publishers, such as yours truly, have to opt books into a service called Select, and make them exclusive to Amazon, for them to be eligible for KU. Which is why there are only two of my books available on it at the moment, and they’re Garth Owen ones. Some, but not all, of my future releases will be exclusive to the big river, so that list will fill up with time.
If you’re a voracious reader and, unlike me, you don’t live next door to a charity shop with a well stocked 20p books table, then Kindle Unlimited could be a neat value-for-money way to get your fix.