TULSA - We've heard from several disappointed drivers who drove up to the pump at Walmart and Murphy USA gas stations, expecting to take a big discount off the posted price.
"I see that Walmart and Murphy USA offer a 10-cent-a-gallon discount if you use their gift card and a 15-cent-a-gallon discount if you use a Walmart credit card," Amanda said. "I've heard that's happening in every state, except Oklahoma, because of a state regulation."
There is an Oklahoma law called the Unfair Sales Act that says a business must mark up its product by at least 6 percent over cost.
So that keeps Walmart and Murphy USA from offering those bigger discounts here.
There are a handful of other states with similar laws.
Walmart's website says Oklahoma drivers can still get its every day discount on gas -- 3 cents off a gallon if you use their gift card and 5 cents off a gallon if you use their credit card.
The Oklahoma Attorney General's office says the idea behind the state's Unfair Sales Act is to keep big companies from running smaller businesses out of business.