If you know of a cheaper unit please post it here.
UNIVERSAL CODE READER
Pinpoint problems the way factory mechanics do. Easy to use. Simply plug the reader into the vehicle's test connector and your car's on board computer will tell the code reader what ails it. Includes instruction manual. Fits 1996 and new vehicles with generic OBDII connector.
http://www.google.com/search?hl=en&rls=com.microsoft%3Aen-us&q=cheap+obd+code+reader&btnG=Search&aq=f&aqi=g1&aql=&oq=&gs_rfai=&gs_upl=4000%2C2609%2C5%2C0%2C91 %2C141%2C1%2C3
http://www.harborfreight.com/catalogsearch/result/?category=&q=obd