I listen audio books because I cannot read very well. My eyes couldn't resist too long reading a lot of text.

But I enjoy audio books, it helps me to sleep and relax me. I wouldn't use a streaming service of audio books. Why? Because I do not want to be connected when I read/listen books. And I mostly listen them when I am away from home, in the wilderness. So I prefer to download the audio file on a small device and listen it.

How much to pay for an audio book? I don't know, but this is the wrong question. Usually the one that create the content is the one that make the price. If the price is not correct, the market will adjust it.

So who is going to make those audio books must do their math:

Price for something start with the start of production not with how much a customer will pay. I will tell you how much a customer will pay: ZERO if is possible.