Pennsylvania motorists are spending a little less at the gas station this week. As reported by Triple-A, the average price for a gallon of regular fell Friday in the Keystone State to three-dollars-37-cents. The national average dipped to three-23 a gallon. Prices remain lowest in Mississippi at two-78 a gallon. Costs for a gallon of gas continue to be highest in California at four-76 a gallon.