PLAINFIELD, Ind. -- A costly mistake at an Indiana gas station early Tuesday morning means the business is out a lot of money.

The mistake at regular unleaded pumps at a Shell station in Plainfield allowed people to fill up for just pennies.

Gas at the station was supposed to be $2.75 a gallon, but customers pulled up to the pumps to find a price of $.002 a gallon.

The mistake was discovered early Tuesday morning, but several customers had already gotten away with a drastically low price fill-up.

The gas station is not exactly sure how many people took advantage of the situation. Since customers paid at the pump, clerks did not have face-to-face contact with the customers.

Driver Kenneth Krebs said he couldn't believe what he saw that allowed him to fill up his truck for 7 cents.

"I pulled into that gas station, put my card in to get gas and hit the 87 octane button and it came up like two-hundredths of a cent," said driver Kenneth Krebs. "So, I proceeded in filling up my truck."

A woman went into the store and told the clerk what was going on, showing her receipt for a few cents for several gallons of gas. That woman offered to come back into the store later Tuesday to pay the difference.

The gas station is trying to determine if it can go back and charge the people who got the bargain regular price after the fact.