You can get an Actron scanner off of ebay that works for OBDII for about $130. Or you could get a program that allows you to datalog like AutoTap for $300 if I remember correctly.
Autozone reads them for free. That's the best bang for your buck. Or you can buy the $50 code reader and do it yourself. Or you can get a handheld programmer for $350-$400 and have a whole lot more.