The higher gas prices go, the more the math on a Costco membership starts to make sense

• Average US gas prices topped $3.60 this week after Trump's war with Iran disrupted oil supplies.
• Costco, meanwhile, sells gas about $0.20 per gallon less than nearby stations.
• The wholesale club's price advantage can be bigger in areas with relatively high gas prices.

President Donald Trump's war with Iran is disrupting oil supplies and sending gas prices soaring, but some drivers are finding relief at their local Costco.

The wholesale club typically sells gas about $0.20 per gallon less than nearby stations, but that advantage can be greater in areas with relatively high gas prices.

For example, on Friday in Atlanta, the Costco warehouse on Brookhaven Avenue had gas at $3.26 per gallon, which was $0.14 below the county averages reported by GasBuddy and AAA.

Although Kansas had the lowest gas prices of any US state on Friday, neighboring Missouri is usually not far behind. In St. Louis, the Costco warehouse was selling gas for $2.99 per gallon, which was $0.27 below the local average.

And in Los Angeles — home to some of the nation's highest gas prices — the Alhambra Costco had gas at $4.99, $0.47 below the county average.

Last month, Business Insider found that in each of 13 US metro areas, drivers who bought 600 gallons of gas a year at Costco saved at least as much on fuel costs as the $65 annual membership fee. In some cases, the savings far exceeded the fee.

Heading into what could be an extended period of gas price volatility, US drivers may be rethinking how and where they spend their money. Membership chains like Costco, Sam's Club, and others could provide some much-needed savings for stretched household budgets.

One Reddit commenter in Texas said last week that conventional gas station prices were up roughly $1 in their area, but Costco's increase was less than $0.40.

The company's CFO, Gary Millerchip, said last week that while it's still too early to know the long-term impact of the current conflict, rising gas prices tend to highlight the club's value perception among members.

"When prices are higher, that will tend to cause members to maybe take the extra mile that it might be involved to get to the gas station because of the incremental value they see there," he said.