Costco vs Sam's Club Gas Prices: Which Warehouse Saves More?

Costco and Sam’s Club have turned fuel into a membership perk, and both routinely post prices 10 to 30 cents below the branded stations around them. The question drivers actually ask is simpler: which one is cheaper where I live?

The honest answer is that there is no national winner. There is a winner at each pair of warehouses, and it changes with the wholesale market.

Why both are usually cheaper

Warehouse clubs treat fuel as a customer acquisition cost:

• Low margin by design. Fuel gross margin at warehouse clubs is typically thinner than at convenience stores.
• High volume. A single Costco pump can sell more gallons per day than several branded stations combined.
• Simple offer. Usually two or three grades, no car wash, no hot food, limited staff.
• Membership revenue. The profit comes from the membership fee, not the gallon.

The result is a station that can sell at a lower price and still make money.

How to compare them fairly

Do not compare the brand names. Compare the specific stations:

1. Distance. A warehouse 12 miles away is not cheaper once you burn fuel to get there. A 10-cent discount on 15 gallons is $1.50; a 24-mile round trip costs $3.50 or more.
2. Line length. A 15-minute wait with the engine idling burns roughly 0.2 gallons — about 85 cents. Subtract that from the discount.
3. Membership cost. Costco’s basic membership is $65 a year and Sam’s Club’s is $50, though both frequently discount the first year. If you would not otherwise join, the fuel savings alone rarely justify the fee unless you buy 1,000+ gallons a year.
4. Payment rules. Costco accepts Visa and debit; Sam’s Club accepts Mastercard, Discover, and debit. If your cash-back card is not accepted, the effective discount shrinks.
5. Grade availability. Both sell 87 and 91–93 octane. Some cars that require 91 are fine at either; some European models specify 91 and are fine with 93.

The membership math

At 482 gallons a year (13,500 miles at 28 MPG):

Against a $65 membership, a 15-cent discount saves about $7 net in the first year — barely worth it on fuel alone. But most members also use the warehouse for groceries, where the membership pays for itself separately. If you are already a member, the fuel discount is pure upside.

For a two-car household using 1,000 gallons a year, a 20-cent discount is $200 — clearly worth the fee.

What about BJ’s and other clubs?

BJ’s Wholesale Club operates fuel stations in the Northeast and Southeast and prices similarly to Costco and Sam’s. Regional clubs and grocery chains with fuel centers — Kroger, H-E-B, Meijer, Wegmans — often run 5 to 15 cent discounts tied to loyalty points, which can match warehouse pricing for heavy grocery shoppers.

The additive question

All three clubs sell fuel that meets federal standards. Costco’s Kirkland Signature fuel includes a detergent additive package; Sam’s Club does as well. The base fuel comes from the same terminals that supply branded stations.

The real quality risk is not the brand — it is a station with old tanks and low turnover. Warehouses have some of the highest turnover in the industry, which is a point in their favor.

When the warehouse is not worth it

• You are 10+ miles away and would not otherwise shop there.
• The line is longer than 10 minutes.
• You need diesel and the location does not sell it.
• You need a grade the warehouse does not carry.
• You are renting a car with a fuel-purchase requirement at return.

The practical answer

Check both warehouses on your normal route once a month. Buy at whichever is cheaper that week, and do not drive out of your way for either. The brand difference is usually a few cents; the location and line difference is what decides whether you actually save money.

For the regional baseline in your state, see the state price pages. For the full list of station tiers, read which gas stations are actually cheapest.