There are so many versions of this scam but the NZ Herald has published a warning about one that is currently doing the rounds: Police warn of car ‘wrapping’ scam It works like this

• Scammer gets in touch and offers you free sign writing
• Scammer sends you a cheque
  

  One of the cheques sent to a “victim” who knew better than to bank the cheque and send the money.

• You bank the cheque
• You send the Scammer the money to a different bank account
• Scammer cancels the cheque
• Scammer disappears
• You try to reverse your payment and are refused

Past versions have involved trademe deals (they send money for what you are selling if you can buy other goodies on their behalf and ship, payment cancelled after shipping) and rental properties (payment to buy the right to view, only they don’t own the property and it’s probably already occupied). Nobody, absolutely nobody, is going to honour this kind of deal. They may seem credible, they may have built up your trust but that’s all part of the scam. Don’t get sucked in, and (I’d advise) don’t even play along.