I was scanning through my wishlist in the Kindle store I saw that on the Kindle page for Goliath by Scott Westerfeld, in the Formats box the Audible book is listed as $5.95. I found to buy at that price I had to click Buy Now from the
Goliath webpage and it opened in Audible listed at a regular price of $5.95. If I logged in to my Audible account first and searched for the book by title, it gave a regular price of $24.49. I didn't have to buy the Kindle book first (and it isn't listed as a Whispersync for Voice book anyway).