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 first Costco fuel station is now pumping gas at 280 Riversound Way in south Napa. The station opened at 10 a.m. Thursday, eight days before the planned opening of Costco's membership ...