The victim gave the seller £200 cash and withdrew a further £300 - making a total of £500 - in exchange for the goods contained in a rucksack.
The victim had been shopping with his family in Sutton High Street on Thursday, 18 February at around 11:30hrs. His wife had gone to get a haircut whilst he went shopping with his son when he was approached by the trickster outside an exchange shop.
The seller offered the man the opportunity to buy an iPhone 6. After expressing an interest, the seller showed him a number of different Apple devices from the seller's vehicle in the Halfords car park.
The devices included an iPhone 6, iPad Air 2 and a MacBook. The seller explained he was selling the items cheap as he needed money to pay his bills. A price was agreed.
Having withdrawn some extra money from a cashpoint, the buyer returned to the car park. The £500 was handed over in exchange for a navy blue rucksack.
Without looking inside the bag, the victim rejoined his wife before returning home where he opened the bag and found several Argos catalogues and cardboard - and no Apple products.
The suspect is described as a white man, aged 30 years approx, 5ft 7in tall, with gingery hair. He was wearing a black baseball cap, black jacket, blue jeans and black shoes. Police are investigating.
Det Insp James Carrington, of Sutton CID, said: "If you are approached in the street with a deal that's too good to be true, it's because it is too good to be true. Make your excuses and move away and call police straightaway on 999."