SHOPPERS say they got discounted goods at the Asda store in Westbrook after tills malfunctioned.
The supermarket on Cromwell Avenue closed this morning with staff unable to use the tills after the system crashed.
It is not yet known what caused the malfunction, although it is now open again.
Sandra Barrett, aged 42, of Meteor Crescrent, Orford, was in the store.
She said that staff were unable to scan items, instead estimating prices and using calculators.
"All the alarms were going off and they said on the tannoy the tills had stopped working.
"Managers had to get calculators, I felt really sorry for them.
"My husband had a basket of stuff and got charged £2 and I think I saved about £8.
"We got a coat for my daughter that was charged as £20.
"We checked online when we got home and it was £25.
"It's a shame but the staff were doing everything they could to help, and even gave out chocolates.
"I don't know why some people left their trollies - they missed out on a bargain."
Other shoppers reported saving around £10, while some said it was 'chaos' after the tills crashed.
One, who did not wish to be named, said: “It’s absolute chaos in there at the moment and I only went in for bread.
“Staff just said the power had gone and asked people to bear with them.
"I don't know how they'll manage, some people were starting to get annoyed."
Asda have yet to confirm details of the incident.