I searched google a bit, and found this one . It looks like the same unit Charlie found at SR.

Do you want just a simple code reader, or do you want a complete OBDII diagnostic tool? There's a big price difference between the two.

Last year I purchased a simple OBDII code reader from Harbor Freight for only 50 bucks. If you go to Harbor Freight and search for item number 46030, you'll find the device (it's only $39.99 now!).

After you have the read the code, you'll of course need the service manual to figure out why the code was triggered in the first place.