Not all fuel stations sell gas that have this designation. So not only might you pay less for gas at Costco, but you might get better mileage out of it. It pays to give Kirkland a chance Costco ...

Napa's Costco gas station does not offer diesel or windshield wiper stations. At another pump, Miranda Ruiz waited in the passenger seat of a car while her friend Julissa Sanchez got gas.