Every Sunday or Monday or so, Amazon releases the "Kindle Exclusives" for the week.
All Kindle Exclusives ebooks are published by Amazon or one of its imprints.
Amazon has a program, called "Whispersync," for some of the ebooks that they sell. With Whispersync, you generally can get the corresponding audiobook to an ebook cheaper than you could by buying the audiobook alone from Audible, even when considering the price of the ebook. With a
Kindle Exclusives ebook, however, you generally can get the corresponding audiobook
even cheaper than you would for the audiobook for a non-Kindle Exclusives. That's the (very) short version; for much more information about the benefit of a Whispersync deal, please look at some posts about it, scattered throughout this thread.
This link gives all of the current Kindle Exclusives ebooks with audio narrations, sorted by price low to high, and with average ratings of 4.0 or more. You can adjust the search to whatever you wish. Note: on the lefthand column you can refine the returned search hits to a specific genre or subgenre.
As for me, I'm going to do a search right away for my favorite subgenre--romance.