Ec-cell1 via eBay offers the Mini OBDII ELM327 Bluetooth Automotive Diagnostic Scanner Tool for $4.14 with free shipping. That's tied with our mention from three weeks ago as the lowest total price we've seen. (Outside of other eBay sellers, it's also a current price low by $2.) 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.