Librivox offers a wide variety of free audiobooks. It is legal, and there is no catch. The books are free, because their copyrights have expired and they are now in the public domain. Moreover, Librivox books are read by volunteers, not actors.

Perhaps listening to a book read by an actor would be more fun, but that costs money. And the volunteers do a good job. In fact, if you are learning English, listening to one of these volunteers can be more useful than listening to an actor, because their English is more natural.

Listening to books in the public domain offers another interesting possibility. Listeners can also download the text and follow along with the audio version.

[hat tip]