Last August TuneIn launched a premium package where you pay $8.99 per month to get access to over 40,000 audiobooks. This is a fairly good deal, because you can listen to all of the content you want, without having to pay extra. There is a large segment of users that want to know what titles are in the catalog before they sign up for access. If this is the case, you might want to check out THIS link. It basically lists all of the audiobooks TuneIn has in their library and lists them in order of popularity.
Michael Kozlowski is the Editor in Chief of Good e-Reader. He has been writing about audiobooks and e-readers for the past ten years. His articles have been picked up by major and local news sources and websites such as the CNET, Engadget, Huffington Post and Verge.