Before we get into those cars with impressively big gas tanks, it's worth creating a frame of reference. On one side are the diminutive runabouts like the Mitsubishi Mirage and its 9.2-gallon tank.

Amazon is offering an end-of-the-year treat to help relieve Americans from record gas prices: For a limited time, Prime members can double their savings on gas. Prime members already enjoy 10 cents ...