Audio Books

DH have gotten into a new ritual of listening to Audio Books on long car rides (I even listen to them sometimes on the way to work-my commute is about an hour).

We have bought a few and have borrowed some from the library (not a great selection).

Anyone know of a good place to buy cheap ones?We listen to everything so it doesn't matter what genre really.

Or, does anyone know of a good audiobook club with good deals?

Thanks!