According to publication, a man who thought he was buying a laptop was conned into paying £400 for a bottle of water.
The victim was approached by a man who showed him a grey rucksack containing a brand new laptop and a mobile phone.
But when the victim went to the ATM to get cash, the fraudster swapped the gadgets for a bottle of water before handing over the bag in exchange for money and driving off.
Officers are appealing for information on the incident which took place in Swindon on Thursday.
A Wiltshire Police spokesperson said: ‘At this time of year many families will feel under pressure to try to afford Christmas and may be looking for deals to save money.
‘However, there are many criminals out there ready to exploit this and unfortunately, this victim fell prey to this fraudster, leaving him seriously out of pocket.’
‘If it looks too good to be true it probably is.’