Warehouse clubs sell gas near cost because cheap fuel brings members through the gate. For drivers willing to carry a membership card, the savings are real: 15 to 28 cents below market price per gallon, which adds up to $100 to $200 per year for an average driver. This guide breaks down six months of real testing data across Costco, Sam's Club, and BJ's to show you which club actually delivers the lowest per-gallon cost.
Expert Note
Warehouse club gas prices vary significantly by region. California Costco locations tend to show smaller discounts relative to market price because baseline California gas taxes are already high. Test your local club against GasBuddy prices for at least two weeks before deciding whether a membership is worth it purely for fuel.
How Warehouse Club Gas Pricing Works
Warehouse clubs use fuel as a member retention tool. Gas is priced near break-even or at a small loss to justify the annual membership fee and increase visit frequency. The club makes its money on membership fees and on products inside the warehouse, not at the pump.
This structure creates a durable pricing advantage. Unlike a retail chain running a temporary promotion, warehouse clubs have a structural reason to keep prices low permanently. The discount is not marketing spend with an expiration date.
Costco Gas
Price and Quality
Costco consistently delivers the lowest raw price among the three clubs, averaging 20 to 28 cents below market in our six-month test period. Costco sells Top Tier certified fuel, meaning it meets a higher detergent standard than minimum EPA requirements. This matters for engine cleanliness over the long run.
Wait Times
Peak hours at Costco gas stations run 8 to 14 minutes average wait time. Weekday mornings and late weekday afternoons tend to be shorter. Weekend afternoons can stretch to 20 minutes. The line length is the main drawback compared to competitors.
Card Stacking
The Costco Anywhere Visa adds 4% cash back on all gas purchases including at Costco. On a 25-cent-below-market fill-up, you are earning the per-gallon discount plus 4% on the discounted price. This is the strongest single stacking combination among all club options.
Sam's Club Gas
Price and Locations
Sam's Club averages 18 to 25 cents below market. It trails Costco slightly on raw price but compensates with more locations, particularly in the Southeast and Midwest. The Sam's Club Plus membership tier ($110/year versus $50 for basic) includes an additional 5-cent-per-gallon fuel discount on top of the standard price.
Sam's Club Mastercard
The Sam's Club Mastercard earns 5% unlimited cash back on gas everywhere, not just at Sam's Club. This is the best gas rate on a card with no annual fee (the card itself is free; Sam's membership is required). For drivers who fill up at various stations, this card works anywhere Mastercard is accepted.
BJ's Wholesale Gas
Price and Footprint
BJ's operates primarily in the Northeast, from Maine to Florida. Prices average 15 to 22 cents below market on a standard day. BJ's membership fee is slightly lower than Costco's ($55 for Inner Circle versus Costco's $65), which can affect annual value calculations for fuel-only members.
Grocery-Integrated Fuel Points
BJ's integrates fuel discounts with grocery purchases made inside the club. Buying qualifying items triggers per-gallon discounts on your next fill-up. During promotional periods, BJ's can briefly match or beat Costco's effective per-gallon price when grocery fuel points stack with the base discount.
Six-Month Testing Results
| Club / Tier | Avg Cents Below Market | Annual Savings (45 gal/mo) |
|---|---|---|
| Costco | 24¢ | $130 |
| Sam's Club Plus tier | 21¢ | $113 |
| Sam's Club standard | 17¢ | $92 |
| BJ's (promo periods) | 28¢ | $151 |
| BJ's (standard) | 16¢ | $86 |
Membership Value Calculation
A Costco Gold Star membership costs $65/year. At 24 cents below market and 45 gallons per month, the annual fuel savings are approximately $130. Membership pays for itself on fuel alone in about 6 months, before counting any warehouse shopping savings. Sam's Club basic at $50 pays off in about 6.5 months at their savings rate. BJ's standard at $55 pays off in about 7.5 months.
Pro Tip
If Costco and Sam's Club are both accessible to you, use the Gas Cost Calculator to estimate annual fuel savings from each and compare against membership costs. Many drivers find that splitting the year between clubs based on route is the maximum-value approach.