I was shopping for a paperback book and noticed Amazon was running a promotion where if I add the book and an Audible membership to my cart I would get $20 off the bundle price. The paperback I wanted was $10 and the membership is $14.95 so with the $20 credit I only ended up paying $4.95 for both and I was planning on signing up for Audible anyways so this was a good deal. It was hard to find the deal on mobile so I recommend checking this out on your laptop. There’s an "add both to cart" button on the product page of the select titles that are eligible for the credit.
https://www.amazon.com/b/?node=178626510