Missouri's Division of Weights and Measures tests gas to make sure the octane level that's posted is what is pumped into vehicles. Lately, inspectors say, Missouri drivers are getting more than what they pay for. That's because, when you mix 87-octane gas with the required 10-percent ethanol, it raises the fuel's octane level to 89.

“Ethanol is high in octane. It raises octane levels up about two numbers,” said Ron Hayes, a laboratory manager for the Division of Weights and Measures.

Hayes says one way to cut costs at the pump is for gas stations to buy cheaper 84 octane and mix it with ethanol to make 87 octane.

“There are a few refineries close to Missouri that are making it,” he said.

Several gas stations in Joplin are already buying suboctane fuel from a refinery in Kansas. Their prices at midday Tuesday were about $3.83 a gallon, about five cents cheaper than in Springfield.

“You might lower the cost by a couple of pennies -- 2 or 3 cents,” said Hayes.

Some drivers welcome the savings.

“It would definitely help a lot,” said one.

Others say it's too little to make a difference.

“Five cents a gallon -- not very much,” said another driver.

After all, if you fill up your 15-gallon tank once a week, even a 5-cent per gallon savings translates to just $40 a year.

“With the cost of living and everything going up, it would take more than five cents a gallon; we would need to take it back to $2 a gallon,” said driver Beth Alier.

Hayes says we won't feel the real impact of suboctane fuel until other states start adopting ethanol requirements that would force more refineries to offer the cheaper product.