I have been out of the consumer electronics game for a bit, but here is what I could scrounge up quickly:
Your cheapest option would be to pick up an internal DVD burner (I don't think you can actually buy a drive that only does CDs any more) for under $20, and a portable CD player for use when out and about. If your car's CD player supports MP3s, all the better, you can get a portable one that does the same.
The down side is obviously that you are a confirmed Luddite, and thus are probably not happy with installing a CD burner in your computer.
Trading $$ for ease of use would obviously be an MP3 player and a mini jack cable to go into your aux port in the car. The advantages are obviously that it's easier, you only need to buy one thing, and most MP3 Players are simply drag and drop for transferring audio.
I would probably suggest looking at the Sansa devices from SanDisk. Far from top of the line, but really, who care?
$30 for a 2 gig player that has a display (cheaper ones tend to not have a display), and is expandable via Mico SD card, which you should pay a bit less than $1 per Gig for.
You might not even need to expand the memory, depending on how many audio books you want to carry around with you at a time (2 gigs of reasonable quality audio books is a good amount)
I personally recommend buying from NewEgg, mainly because most of the brick and mortar stores are not going to actually have non-top of the line players.