Costco and other warehouse stores have become a popular option for affordable gas.

Besides its large format and bulk item offerings, Costco stands out from other stores by requiring a membership to shop there. And while paying an annual fee may be off-putting to some, many customers find that it's worth the once-a-year charge to access the big deals they can access with their club card. This includes access to discounted gas, which some financial experts point out has become a major draw for warehouse stores such as Costco, Sam's Club, and BJs as record-high prices plague the pumps.

"They often do seem to come in 10, 15, 20 cents below other stations," Ted Rossman, a financial analyst with Bankrate.com, told News 12 in Long Island, New York, during an interview in March. But now, Costco has announced it's changing how customers can use this service going forward.

Costco will be making a major change at some stores starting July 5.

Now, drivers in some states may not find the discounts they've been enjoying when they go to fill up. According to signs posted at Costco pumps throughout New Jersey, only customers who pay the store's annual dues will be allowed to buy gas, the Courier-Post reports.

"Effective July 5, 2022, your active Costco membership card will be required for gasoline purchases," the notices advise.

The news comes as the average price of gas in New Jersey slipped above $5 per gallon to $5.019, according to Channel 12 News from the Bronx, New York. As of June 7, the cost of a gallon of gas at the Bayonne, New Jersey Costco location was $4.81 per gallon.

Only stores in one state previously offered gas to non-members.

Costco's gas station situation in New Jersey has been unique since 2004, when authorities told the warehouse retailer that requiring a membership card to fill up violated state law, according to the Post Courier. But after nixing the requirement for nearly two decades, some say the company may be in the right to reinstate it.

"I am learning they (Costco) are taking a position that it is not illegal to limit their customers to members at their New Jersey gas stations, and I see nothing in state law that prevents them from doing this," Sal Risalvato, executive director of the New Jersey Gasoline Convenience Store and Automotive Association, told the Post Courier.

But those on the other side of the pump say they're unsure about the recent policy shift. "I always had to use my Costco card in Ohio, but here in New Jersey, they never ask for it," Costco Gas customer Carnita Brown told the Post Courier. "I wonder why it's going to change ... and I have no idea if it's legal to do that here."

Certain non-member card holders can still buy gas at Costco.

Even though warehouse retailers' pumps may be off-limits to the public, experts point out that there's still a way non-members can access the lower prices. Costco says that while membership is required to fill up in their stations, "there is an exception" for anyone who pays with one of the store's gift certificates known as Costco Shop Cards.

However, getting your hands on this special access can be a complicated process. Since only members can purchase Shop Cards, it may require asking someone you know with membership to buy them for you, either at warehouse locations or on the company's website, MoneyTalkNews reports.

But ultimately, some experts argue that the added trouble may not be worth it in the end, especially given the popularity of Costco pumps. "If you are going to wait in line for gasoline for 45 minutes to save 15 cents a gallon or even 20 cents a gallon, what did you save? You didn't save anything. You burn that much gas waiting for the pump to be opened," Risalvato told Channel 12.

READ THIS NEXT: Lowe's Is Making This Big Change In Stores, Starting Today.