Okay, this is the secret sauce. If you own the Kindle version of a book, you can often add the Audible narration for a reduced price. Sometimes it’s as low as $1.99. Prime doesn’t give you the audiobook for free, but it does give you a discount on the Kindle book if you’re a Prime member.
So, you buy the Kindle book (often on sale), then add the audio for cheap. You get both formats. It’s like buying a pizza and getting free garlic knots. Not truly free, but so close it feels like a win.
