Gas prices officially suck. But not all of us own hybrids, bikes or electric vehicles. Luckily, all is not lost. For $79, you can purchase a gadget that teaches you how to drive fuel efficiently: the EconoDriver from Lemur Vehicle Monitors. The EconoDriver has two parts: an OBD-II port sensor and a keychain reporting device. The sensor plugs into a vehicle’s electronics system under the dash and sends information wirelessly to the keychain, which (after you enter the current gas price and your engine size) displays your miles per gallon, cost per trip, and a one-to-five “leaf” rating on how efficiently you drive.