It is no secret that gas prices are on the rise across the nation. But locally, it seems like the margin between cash and credit prices at local stations is increasing as well.

In an impromptu survey of township filling stations, about half are charging more money per gallon – about 10 cents on average – for customers who use credit or debit cards to fill their tanks. Often, those stations that do not charge more for the use of a card have higher base prices to begin with, however.

It is perfectly legal for gas stations to charge more if a customer uses a credit card and it does not violate gas stations' contracts with credit card companies. The experts say the trend is likely to grow.

They can be blamed on a low profit margin, according to Fred Rozell of the Wall Township-based Oil Price Information Service (OPIS).  

Rozell is the Director of Retail Pricing for the internationally recognized organization.

"The average profit per gallon sold for a local gas station was about 18 cents in 2011, but the profit has been as low as 9 cents in recent years. It averages about 14 cents a gallon," Rozell said.

OPIS estimates that credit card fees for gas stations range from 2.5-3 percent of sales. The Association for Convenience & Fuel Retailing says that credit and debit card fees averaged 4.7 cents per gallon when factoring in all gasoline sales (cash or credit) in 2009.

"It's hard to operate at such a low profit margin when most of these stations are probably only doing about $50,000-$80,000 of business a month.

On Monday, the price for a gallon of regular fuel for customers paying with cash was $3.39 at the Exxon station on Brick Boulevard, near Brick Plaza. Use a card, and the price jumped to $3.49 per gallon. Likewise, there was a ten cent difference between cash versus credit pricing at the Lukoil on Brick Boulevard, the Exxon on Drum Point Road and Sandy's on Mantoloking Road.

Brick's newest gas station, the Wawa location on Brick Boulevard, was steady at $3.39 no matter how a motorist paid. They can afford that, Rozell said.

"Wawas are doing about $500,000 a month in business, and the trick is they're getting people inside. If a gas station doesn't have a popular convenience store, they're in trouble," Rozell said.

Ironically, the lowest price overall in Brick on Monday was a station where cards are king: Costco. A gallon of regular gas there cost $3.31.

The cost at the Singin location on Chambers Bridge Road, another station where customers pay the same price, came in at $3.35. At the Liberty station on Mantoloking Road, a gallon of regular was going for $3.44.

Prices for premium fuel ranged from $3.55 to $3.78 at the stations surveyed.

Local representatives from Wawa, Exxon and Shell did not return Patch's phone calls about their profits and credit fees.

Motorists are noticing the price difference in a big way, however. Patch readers discussed their opinions on the matter at Brick Patch's Facebook page on Monday.

"I only pay in cash," said Kathleen Woodley Strittmatter. "I understand that they have to pay a fee for the credit card service to the bank so they have to make it up somehow. However, they won't get it from me."

"Does Walmart, Target, or any other store charge you for using credit cards? Cost deferment should never be clearly reflected so obviously to the customer," said David Clark. "Gas stations are getting out of control because gas is a necessity."

Some readers were understanding – to a point.

"It makes sense if they are being charged by the credit card companies but it should fairly reflect that cost, no more," said Mary Ellen McCandless Ryder. "If I pay cash, I don't want to pay more to cover people who use [credit cards]."

Rozell says consumers shouldn't see an increased credit price as a penalty, but instead as a nature of the business.

And if you're looking for relief at the pump any time soon, think again.

"Prices should remain erratic through the spring, but we could hit record levels before Memorial Day" according to Rozell.