The mini-compact MINI Cooper, equipped with a four-cylinder 1.6-liter engine, can achieve 28 mpg in city driving and 37 on the highway, while the automatic gets 25/34. The MINI takes 0.78 gallons of fuel to travel 25 miles at a cost of $2.20. Total mileage on its 13.2-gallon fuel tank is 380. Total annual fuel cost is $1,324, according to the EPA.