Audible has a free app. This book is free on Amazon and you can listen to it for free, just like when you get free ebooks or digital music and then play it on a free app or reader on your electronic device. It only costs money to buy individually priced Audible books or sign up for a monthly subscription for Audible service where you get to read many books.
Yes, Amazon is good about keeping your account active even if you cancel early. Also note, if you do get the free trial and decide to cancel, they will extend your trial period or sweeten the deal. On top of that, you get to keep the books you downloaded. With Prime you have access to a limited amount of pod cast and books for free.
Looks like buying this free audiobook signs you up for the audible service which will be billed to your credit card if you don't cancel. And I think if you cancel audible you can't listen to the book. So not really a deal is it? (Am i wrong?)