PHILADELPHIA -- Hate it when you fill 'er up and, five minutes later, spot another station selling gas for a nickel a gallon cheaper?
Jason Toews, a 30-year-old computer programmer from the Minneapolis suburbs, hated it even more when he couldn't find an easy way to shop around.
"I even tried calling up some of the stations to find out what their prices are and they usually didn't like to tell you over the phone," he said. "They think it's one of their competitors."
Toews started the nonprofit GasBuddy Organization Inc. four years ago with a friend, chronicling regular unleaded prices in the Twin Cities. The site was so successful that he and co-founder Dustin Coupal, an ophthalmologist, expanded nationwide.
Now, the gasbuddy.com portal links to 173 price comparison Web sites with names like phillygasprices.com, wichitagasprices.com and miamigasprices.com, with 50 more local sites coming online this fall.
Price-sensitive motorists are flocking to the Internet to shave their gas bills - and, perhaps equally important, for the psychological satisfaction of knowing they have some control over what they pay.
"I'm cheap. I'm not paying more for something than I have to," said Christina Klein, 40, who uses the Philadelphia site daily and doesn't mind driving a little out of her way if it means saving a few pennies per gallon.
The GasBuddy network surveys an average of 150,000 stations per week in all the U.S. states and Canada. At phillygasprices.com, volunteers check hundreds of Philadelphia-area gas stations per week and post their findings on the Web; prices are automatically sorted from lowest to highest.
When gas shot up to more than $2 a gallon earlier this summer, traffic to the GasBuddy sites increased sevenfold, to about 500,000 unique visitors a week, Toews said. It has since dropped to 150,000 to 200,000 a week - although that could spike again if gas prices rise, as many analysts expect.
Another Internet site, for-profit GasPriceWatch.com, reported even greater traffic, peaking at 300,000 visitors on June 6 alone.
"Our participation is directly proportional to the price of gasoline," said Brad Proctor, founder of GasPriceWatch.com.
The Web sites work similarly, relying on volunteers to report prices and advertisers to either pay the bills or turn a profit. Visitors enter their zip codes to find prices at nearby stations.
About 270,000 people have registered as volunteer gas price reporters for GasBuddy. Some people post prices once or twice a month, while others are fanatical about the site, reporting every day, Toews said.
Centerville, Ohio-based GasPriceWatch.com said it has more than 100,000 price spotters.
Gas prices are influenced by a complex array of factors, including supply and demand, the price of crude oil, refinery costs, taxes, and competition among gas station owners, so it's unlikely that the Web sites have much of an effect on pricing. In Pennsylvania alone, hundreds of thousands of motorists pump more than 10 million gallons of gas into their cars, trucks and SUVs each day, dwarfing the relatively small number of people who frequent the pricing sites.
Holly Tuminello, vice president of the Petroleum Marketers Association of America, a trade group of 8,000 independent gas stations, said she doubted that gas station owners relied on the Internet to check competitors' prices and set their own accordingly. The price of gas changes so frequently that price reports more than 24 hours old are likely outdated, she said.
But Tuminello said the sites still perform a valuable service - and she doesn't blame motorists for using them. "Good for them. These prices are high and everybody loves a bargain," she said.
Cindy Reimel, 43, a corporate accountant who occasionally reports prices for phillygasprices.com, figures she and her husband save nearly $10 a month by using the Internet to shop for gas, out of a total monthly bill of $200 to $300.
"I need to fill up once every five days and I have a minivan that takes a lot of gas," said Reimel, who drives 20 miles to work. "I'll take a different route if the gas is cheaper."
On the Net:
GasBuddy Organization: http://www.gasbuddy.com
Petroleum Marketers Association: http://www.pmaa.org