Arizonans Facing High Pump Prices Can Often Cut the Bill at Costco and Sam’s Club. A Petroleum Analyst Explains Why
Watching the gas pump numbers climb while you stand there is no fun.
A warehouse club’s gas station may cost you less than the one down the street.
Here’s why gas at Costco and Sam’s Club often costs Arizonans less.
Note: This is general information, not financial advice. Gas prices and membership fees are subject to change.
Where Gas Prices Stand
As of Oct. 4, AAA listed the Arizona average for a gallon of regular at $4.75.
The national average was $4.37, so Arizonans pay more.
A year earlier, Arizona’s average was $3.53.
That’s $1.22 more a gallon.
On a 15-gallon fill-up, you’re paying about $18 more.
A week earlier the average was $4.82. A month earlier it was $4.53.
You’re paying about 22 cents more a gallon than then.
The Bureau of Labor Statistics covers the West region, which includes Arizona.
There, regular gas prices rose 24.8% over the 12 months ending in August.
In plain terms, $100 of gas a year ago now costs about $124.80.
AAA’s Oct. 1 report ranked Arizona ninth among the most expensive gas markets in the country.
California, Nevada and Utah, three of Arizona’s neighbors, all ranked higher.
Inside Arizona, AAA’s Oct. 4 metro averages ran from $4.50 in Tucson to $5.00 in Scottsdale.
Phoenix-Mesa was at $4.81.
So a club discount starts from a different baseline depending on your metro.
Warehouse Club Gap
Costco’s gas stations often sell gasoline for 10-30 cents a gallon less than nearby name-brand stations.
The Arizona Republic carried that USA TODAY reporting in late March.
The Republic described Costco’s base price as consistently among the cheapest.
At Sam’s Club, you’ll typically find prices 10-30 cents below the local average, USA TODAY said.
Those are late March numbers.
Back then, the Republic cited AAA’s Arizona average at $4.63 a gallon and the national average at $3.98.
It also cited AAA’s Phoenix-area averages that week. They ran from about $4.87 in Phoenix-Mesa to about $4.95 in Peoria.
The Math on a 15-Gallon Fill-Up
Say Costco’s gas runs 10-30 cents under nearby stations, as USA TODAY reported. Then a 15-gallon fill-up costs $1.50 to $4.50 less.
A $65 Costco Gold Star membership in the U.S. would pay back in about 44 fill-ups at $1.50 saved each time, or about 15 at $4.50.
A $60 Club tier membership at Sam’s Club would pay back in about 40 fill-ups at $1.50. At $4.50, it’s about 14.
A $120 Plus tier membership at Sam’s Club would pay back in about 80 fill-ups at $1.50. At $4.50, it’s about 27.
Fill up 15 gallons once a week, and the same gap adds up to $78 to $234 over 52 weeks.
These figures cover gas savings only. Your tank size and the day’s prices will differ.
Thinner Margins on Gas
Costco and Sam’s Club can charge less for gas because both take a smaller profit on each gallon.
That’s according to petroleum analyst Patrick De Haan of GasBuddy.
De Haan made that case to Nexstar Media News Wire in a May 2025 interview.
The Arizona Republic repeated it in March 2026.
He described gas as the draw that brings you into the warehouse.
Once you’re inside, De Haan said, people tend to buy more items that earn the store a bigger profit.
Psst! How ready are you to fill up at a warehouse club? Run through this checklist and see where you stand.
Membership at the Pump
Costco’s gasoline Q&A page says its fuel station is members only. The exception is customers who pay with a prepaid Costco Shop Card.
That’s the catch.
Sam’s Club lists “Member Only Fuel Prices” as a benefit of both its Club and Plus tiers.
Its membership page puts the Club tier at $60 a year and the Plus tier at $120.
The Arizona Republic listed Sam’s Club’s regular membership at $50 as of late March.
So check the current fee before you count the payback.
You’ll want a card in your wallet before you pull up.
The yearly fee is part of what you pay for a gallon that may be cheaper.
The Arizona Republic said the Costco Anywhere Visa Card by Citi gives 5% cash back on Costco gas.
That’s on the first $7,000 spent per year. The Sam’s Club Mastercard gives 5% back in Sam’s Cash on gas.
That’s on the first $6,000 per year.
The 10-30 cent range comes from what USA TODAY found in late March.
It’s no promise for any single pump.
What Costco Says About Its Fuel
If a 10-30 cent gap makes you wonder about fuel quality, Costco’s gasoline page has some answers.
Keep in mind, these are Costco’s own claims.
The page says Costco’s goal is the best quality fuel for the best value to members.
It says its fuels are certified to meet TOP TIER performance standards.
It also says Costco filters its fuel so sediment and water don’t get into your car.
And it says Costco has introduced additive technologies for both modern and older engines.
Club Prices in the Phoenix Area
The Arizona Republic checked prices on March 28 at Costco and Sam’s Club gas stations in the Phoenix area.
It used prices that GasBuddy.com users reported.
It listed only the lowest prices GasBuddy users reported.
So read them as the low end, not the price at a typical pump.
The lowest Costco price on the list was $4.29 on South Sossaman Road in Mesa.
That’s about 58 cents under AAA’s $4.87 Phoenix-Mesa average that week.
Seven other Costco gas stations were listed at $4.39, about 48 cents under.
The lowest Sam’s Club prices were $4.34. One was on North Gilbert Road in Gilbert. One was on East Rio Salado Parkway in Tempe. Both were about 53 cents under that same average.
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