Pro Tip: Click here to purchase a Kindle Unlimited subscription from Amazon and read as many eBooks and you want. If you decide that you want to have access to audio books, then become an Audible member on with Amazon instead. You also get to listen to Audible books on Kindle Unlimited, but your options aren't as varied.
Kindle Unlimited (found on Amazon, here) is a subscription that gives you access to eBooks. You're able to download and read as many books as you choose by making a monthly payment of $9.99. Kindle Unlimited includes 2,000+ Audible books that get narrated by a professional reader. However, if you want more audio book options, subscribe to Audible (purchase form Amazon, here) for $14.95 per month.
Choosing between Kindle Unlimited and Audible is tricky because you've got to know your preferences. Luckily, both these options provide a 30-day free trial. You're able to test them out and see which one works best for your lifestyle.