There are many places where one may go and download free audtio books. This posts lists 10 locations, providing a brief explanation for each. The sites vary with some geared to to children and others to adults. Audio books are great for students whom may struggle with reading, as well as for long drives and walks. And all these sites are legal. They host books in the public domain.
My 12 yr old son loves his audio books
These look like good places to get books. I have been trying to get more into electronic books, so these look like good places to start.