PodioBooks

Interesting site for getting audio books for free. They function on donations only. Here is an excerpt from their Donations Page:

This isn't going to be a tear-jerking plea for your cash, and I'm not going to try and convince you that starving authors will continue to go hungry if you don't pass some bucks his or her way. Instead, I'm just going to tell you The Master Plan of how you can make the world a better place.
I'm a child of capitalism, just like many of you. Truth be told, it's supply-side economics, which is a conversation for another time. As good little capitalists, we expect to pay for things, and we expect to get paid for things. Groovy.
We've also become accustomed to artists and creative types getting shafted by The Man. Drop $15 bucks for the latest CD by your favorite artists, you just gave the band a nickle. Which they have to split. Five ways. That beautiful new hardback you just shelled out $24.99 to read? The author saw just under two bucks. Another dinner at Taco Bell™ is in order.
So we've taken that model of accepted commerce, and turned it on it's head. With Podiobooks.com, you decide if something is worth supporting. The author spends time, energy, and often times very real dollars on making each of these chapters. Here on the back side, the costs to do all the tech stuff are greater than zero. But that's OK. We're not begging. Authors and techies alike are doing this to get good books spread around far and wide.
But if you want to donate, you can. We use PayPal to handle all of our payments, and the bulk of your donation goes to the author, not the site. We started out giving half of the money to the author, and now we're up to 75%. That's before PayPal fees, by the way. We absorb those costs (and many others) on the back end.
Check it out at: Podiobooks.com