Smaller cars generally have gas tanks that hold 12 gallons worth of gas, while larger cars can hold 15 or 16 gallons. For the purpose of this story, let's say gas costs $3.85 a gallon. A car with a 12-gallon tank costs $46.20 to fill up while a larger car with a 15-gallon tank costs $57.75.Jul 5, 2013read more >>