So you think you are finally getting one over on the gas stations as you pay well under $3 a gallon for the first time in four years? Guess again. Gas stations love low prices too—and not just because customers are nicer when they are paying less. “We’re in the same shoes as the consumer, the cost of fuel is less for us,” says Kevin Beyer, who owns Performance Fuels, a filling station and convenience store in Smithtown, NY. That means profits for Beyer and the nation’s 127,000 filling stations are rising. Before they sell gas to you, station owners...