Fuel efficiency is one of the main factors that Americans consider when buying vehicles. A car with high mileage not only saves money but also reduces oil dependence cost, increases energy sustainability, and reduces your carbon footprint. The demand for fuel-efficient vehicles has grown more than ever, and most cars in the market have a decent mpg. If buying a new car is out of question, and you are looking for gas-efficient models at Dallas car auctions or anywhere else across the U.S., we list the top four models to consider.