sgbyincons via eBay offers this OBD2 Bluetooth Automotive Diagnostic Scanner Tool, model no. ELM327, for $5.20 with free shipping. That's tied with last week's mention and the lowest total price we could find by $3. This wireless Bluetooth device scans OBDII codes for 1996 and newer cars, light trucks, and SUVs to reveal the reason you're getting a "check engine" light on your vehicle.
Expect shipping to take up to six weeks.