Calling all audio book lovers!

I have come up with the awesome-in-theory plan of using my elliptical time to listen to books on my iPod. I am planning to start with Philip Pullman's His Dark Materials, which I have read multiple times but which I MUST MUST MUST re-read (or hear read) before The Golden Compass is released in December. (By the way, I was flipping out during the preview for it in the theater and was positively overstimulated by the time the Potter, which I was there to see, started.)

Anyway, I was just going to buy the books to download. Expensive. Like $25-$30 per book. I might as well buy the actual CDs so that I could also maybe listen to them in the car as well, right? Then I considered joining one of the audio book rental clubs like audible.com, at least for a short time at a reduced special offer price (about $8 a month for three months), but then I realized you only get one book per month.

Any ideas? Should I just suck it up and buy them? I am not usually such a cheapo, but the money. . . it is tight.