Data point: Costco outside my work has gas for $2.61. Across the street is a gas station selling for $2.98. In my experience I save about $4-5 per tank buying a

Data point: Costco outside my work has gas for $2.61. Across the street is a gas station selling for $2.98. In my experience I save about $4-5 per tank buying at Costco. I fill up about every two weeks, so I save about $100 per year on gas. If you are new to Costco you will typically save nearly the full membership cost on your first trip, stocking up on basic house supplies.