The United service station opened on Peisley Street on the weekend selling all types of fuel for about 25c a litre cheaper than other outlets across Orange and most of NSW.

On Monday E10 fuel at the new outlet was selling for 113.9c a litre, unleaded 91 for 116.9c, diesel 122.9c and high-end 95 octane fuel was 128.4c.

Franchisee Karthik Myana, who also operates the United service station on Woodward Street, said they had been flat out as word had spread about the cheap fuel.

"I am the franchisee here, United has the fuel. I don't know how long it will keep going. It might be a couple more days. I don't know," he said.

"We have been really very busy. Half of the town was here [on the weekend]," he said.

"Everything is really [about] 25c cheaper. It's a special price for the opening."

Mr Myana said motorists from around the region had bought the cheap fuel.

"I have had some come from Canowindra, some from Bathurst, some from Cowra," he said.

In contrast he said trade at the Woodward Street station, which is selling fuel for about the same price as other service stations across Orange, had been quieter.

"It was quiet there, but we've still got our regular customers," he said.

Mr Myana, who has run that service station for about four months, said United did not offer the same special deal of cheap fuel when that venue opened.

Both premises also have a Pie Face shop as part of the operation.

The state government-run Fuel Check website, which provides real-time fuel price information confirmed it was the cheapest price of fuel in NSW on Monday.

It was also well below the average lowest monthly price for NSW for the past year.

For E10 fuel the lowest average monthly price was 121.8c a litre in January - some 8c dearer than the Peisley Street price.

Customer Shane Chislett of Orange said he happily filled up the tank of his car when he saw the price. "I was just driving past," he said.

In contrast to Orange having the cheapest fuel motorists in Tweed Heads and Edgecliff on Monday had the dearest petrol prices in NSW.

They had to pay 163.9c a litre, some 50c more.