Bought a hamster house from Tesco yesterday which stated £1 on the box. Goes through the til at £8. Don't say anything, pay for it then go to Customer Services and get them to refund you the price so it's £1.
Tesco then return double as a way of saying sorry meaning for a £1 spend you then get a £14 refund! Halfed our shopping bill yesterday.
Instore only I believe!