2005 Toyota Prius
The only surprise here might be that the Prius is classified by the EPA as a midsize car. Otherwise, when highway mileage is rated at 51-mpg, the fact that the Prius ranks number one is pretty much a no-brainer. Passenger volume is listed as 96 cubic feet, but most everyone will tell you the interior feels more spacious. The Prius starts at about $21,500.