PHILADELPHIA (CBS) – Everywhere you turn gas prices are going up, up and up!

With no end in sight, some drivers are heading online to Gas Buddy, AAA’s Fuel Finder, and MapQuest. These sites claim to help you find the cheapest gas around.

But 3 On Your Side found they aren’t always accurate.

For example, at a Lukoil station on Delaware Avenue in Philadelphia, the AAA site lists a price of 3.59 a gallon, but there’s a lower price. It’s $3.49 if you pay with cash.

That’s a dime a gallon savings. So, why the discrepancy?

“Nationally we draw credit card info from 100,000 gas stations from around the country,” said Rick Remington with AAA.

Remington says since their price information is based on credit card transactions, cash prices aren’t taken into account.

MapQuest uses credit card information too and like AAA, it updates the prices on its site multiple times a day. Even so, a Sunoco at Ashton and Willits in Philadelphia is charging $3.35 per gallon yet both MapQuest and AAA sites have it as $3.31.

And the AAA site had been updated 2 hours earlier.

Part of the problem is that in Pennsylvania gas stations can change prices as often as they want

“It’s kind of Wack a Mole. We put up a price and it’s going change overnight,” said Remington.

When checking the Gas Buddy app on a smart phone, they had it wrong too.

The Gas Buddy app was downloaded 10,000 times an hour last week and relies mostly on volunteer spotters to post prices, which can include discounts for paying with cash.

In our random checks, those spotters seemed more likely to get the price right.

But the system isn’t perfect either. At a Cherry Hill Gulf station, Gas Buddy listed a price of $3.22 a gallon. The actual price was $3.24 and Gas Buddy never mentioned the seven cent savings when paying with cash.

So if you heading online before hitting the road, just keep this in mind

“It’s not gospel, it’s a guide,” said Remington.

In New Jersey, gas stations can’t change prices more than once in a 24 hour period. N.J. Turnpike and Parkway prices change once a week, Fridays usually around 7 a.m.

All three sites do have disclaimers which point out that they can’t guarantee the accuracy of the prices posted as they can change at a moments notice.

Watch the video…

Reported by Jim Donovan, CBS 3

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