Bigger Gift via eBay offers this OBD2 Bluetooth Automotive Diagnostic Scanner Tool, model no. ELM327, for $4.55 with free shipping. That's a buck under our mention from three weeks ago and the lowest total price we could find now by $2, outside of other eBay sellers. 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 eight weeks.