With the conflict in Iran pushing gas prices higher, Costco’s fuel program has quietly become one of the most effective ways for consumers to cut expenses. Even as national averages climb, Costco’s gas is typically $0.05 to $0.40 per gallon cheaper than local competitors’, savings that can be crucially efficient during a price surge. Costco’s edge comes from its membership model. A $65 Gold Star or Business membership, or the $130 Executive membership, unlocks access not only to the warehouse...