Drivers in Bismarck got a pleasant surprise while filling their gas tanks Wednesday. Gas prices dropped 15 cents Wednesday morning, to $2.99 per gallon of unleaded regular gas at most gas stations, but some gas stations have not changed their prices yet.

Wayne Wenstrom, president of the North Dakota Petroleum Marketers Association, said gasoline prices are based on wholesale prices established mostly by the New York Mercantile Exchange. The prices are affected by holidays, agriculture needs and other factors.

"Retailers are not gouging their prices," Wenstrom said. "Very few of them are making money on the gas at all."

Although to some drivers, $2.99 still seems like a lot to pay for a gallon of gas, a 15-cent decrease is significant.

"We've had complaints that the gas prices go way up and don't go down as quickly, but this time they've dipped dramatically," Wenstrom said. "A 15-cent decrease is pretty big as far as the history of gas prices go," Wenstrom said.

Some drivers at the pump had not even noticed the price change. Ginger Wilkens, of Bismarck, filled up her Geo Metro on Wednesday afternoon at the Stamart Travel Center, at 3936 E. Divide Ave.

"I didn't even notice it changed," she said. "It doesn't matter that much because I get 40 miles per gallon."

Wilkens, who lives out of town, said she has switched to driving the Geo Metro more than her pickup when she comes to town to save on gas.

Ben McConnell of Fargo travels to Bismarck at least once each month to serve in the National Guard.

"It's an expensive drive with high gas prices," he said. "I buddied up with another guy coming here to save gas costs."

McConnell said he was able to avoid filling his gas tank during the past week while prices were so high, but still appreciates the lower price. "Any difference in gas price is better than before," he said.

(Reach reporter Katie Brown at 250-8225 or katie.brown@;bismarcktribune.com.) (Reach reporter Katie Brown at 250-8225 or katie.brown@;bismarcktribune.com.)