News3. Which cars are most economical?Words ByWhat Car? Staff Need a valuation?Obtain a FREE used car valuation for any vehicle.GBCondition…PoorGoodExcellent 3 Feb 2011 17:00 Which cars are most economical? You can see a list of cars that average over 70mpg here. You can see a list of cars that average between 60 and 70mpg here.