I spotted a Pioneer CD player with an aux in and a USB in on the front panel at Wal-Mart for $77. That's only slightly more than a good FM transmitter.
I think it was this stereo without the speakers.
http://www.walmart...-Speakers/15140328 If my speakers were old and crusty, I'd look for the whole kit. It can't be worse than the OEM stuff. Heck, you could probably sell the speakers to some guy wearing a sideways hat that drives a civic for $20 a pair.