Reuben Scheidt was sure he'd been cheated.
The gas he'd paid for Tuesday, at $3.09 per gallon, was 3 cents more than the price advertised on a sign at an Enmark station near his home in Beaufort.
Or so he thought.
Scheidt had seen the lower price of the two posted on the station's sign on the Parris Island Gateway and assumed it referred to the cost of regular gas. It did, but only for those who had an Enmark-issued "cash card."
"It kind of disturbed me," Scheidt said. "I always look for the place with the cheapest price on the board. It felt like it was false advertising."
The practice may confuse some, but it's entirely legal, according to the S.C. Department of Agriculture, which oversees operations of about 70,000 gas stations statewide.
"Stations have to have a qualifier both on their sign and at the pump," department spokeswoman Becky Larson said of the fuel card distinction, which she called "multi-tier pricing."
She added that gas stations found to be charging a price different than advertised can be issued a "warning order" and may receive a "stop order" for subsequent violations, which would immediately halt their gas sales.
The Department of Agriculture investigates claims like Scheidt's, and people who feel misled can check with the agency.
"I'm sure that we've had cases like that in the past," she said, though she was unaware of any ongoing investigations.
Attempts Thursday to reach a representative of Savannah-based Enmark were unsuccessful.
Another Savannah-based gas station, Parker's, recently won a legal battle against the state of Georgia to advertise both sets of prices on its signs.
Its president and CEO, Greg Parker, cited the First Amendment in arguing that prohibiting the signs' display constituted an impermissible regulation of commercial speech.
Regarding the need for such a practice, he said the strategy reflected the unique brand of competition in the gas industry.
"There's no other business like it, where prices of competitors are advertised directly across the street from each other, is there?" he asked, pausing for emphasis. "It's an apples-to-apples comparison."
He instituted his company's "PumpPal" card program in March 2011 to discourage customers from using credit cards.
"We were aghast at how much MasterCard and Visa were charging," Parker said, contending the companies were making 50 percent more profit than gas stations just by processing credit-card transactions.
In 2006, Enmark addressed that issue by lowering prices by 3 cents per gallon for customers who elected to pay with cash or a check instead of a debit or credit card.
The PumpPal cards also create customer loyalty, Parker said, estimating they are used for nearly half of all transactions at his gas stations. He said almost 52,000 PumpPal cards have been issued since last March.
But the proliferation of gas station-issued cards is of little consolation for Scheidt.
"If I find (a station) with an accurate price on its sign," he said, "I'll probably go there instead."
Follow reporter Grant Martin at twitter.com/LowCoBiz.