Queues formed at a petrol station when a misplaced decimal point meant petrol was sold for just 12.9p a litre.
Dozens of drivers took advantage of the unexpected offer at Asda's store in Rooley Lane, Bradford, West Yorkshire.
Some motorists filled petrol cans as well as their tanks. Some reports said the queue became so long, that police had to be called.
An Asda spokeswoman said about 50 customers purchased petrol before the error on the automatic card-payment fast-lane pumps was spotted.
Yesterday, an Asda spokeswoman confirmed that an error had been made involving a decimal point. She said: "For a couple of hours some lucky customers got some petrol at the wrong price."