Five-year cost to own: $30,625. The Toyota Prius Prime is a plug-in hybrid hatchback that essentially adds a larger battery to a standard-issue Prius hybrid and can run for the first 25 miles solely on electric power, provided it’s fully charged. Once the battery becomes depleted to a certain point it runs like a normal hybrid and its range is limited only by the amount of gas in the tank. In EV mode it gets the money-saving equivalent of 133 mpg, with combined city/highway fuel economy at a still-stellar 54 mpg in hybrid mode. A $4,502 federal tax credit more than makes up for the $3,600 premium the Prime carries over a base Prius.