£20 for Charge Spoon Titanium?

^ Yeah, an "invitation to treat" or something like that.

Loads on council web sites, e.g.http://www.telford.gov.uk/Advice+benefits/Trading+standards/Trading+Standards+FAQs.htm

Q. I have seen a CD player on sale in a shop that I want to buy. However, when I tried to buy it the manager told me it was the wrong price. Can I make the shop sell it to me at the displayed price?
A. No. You cannot make a trader sell anything to you if they don't want to. In civil law when goods are displayed in a shop, a catalogue or an advertisement, this is called an 'invitation to treat'. This means that it is an invitation for the consumer to make an offer to the shop to buy the goods, and it is up to the shop whether or not they want to accept that offer.
However the shop might have committed a criminal offence. This is because the Consumer Protection Act 1987 says that traders must not display misleading prices. You could report this to Trading Standards who may investigate the matter, however if this was a 'one-off' genuine mistake they would be unlikely to take any action.