Marsh said the motorhome "seemed like a really good buy".
He tried ringing the phone number in the advertisement, but was unable to leave a message, so emailed the address given.
He received an email back, and began the process of buying the vehicle, which appeared cheap, as the model would have sold for more than $80,000 two years ago.
There was an online application for a secure payment site similar to PayPal, which required proof of identification, and his ability to pay.
He received an email saying he has been successful, and the motorhome was his.
He was sent a form to deposit the money in what was an ANZ trust account.
But the next day he was sent an email saying the account had changed, "which rang alarm bells for us".
It was at that point Marsh began to do some digging. Having been sent photos of the vehicle, he was able to check its registration number and track down its owner.
"I found out the guy that owns the campervan still lives in Bluff, and he's quite happy with his campervan."
The photos he was sent were taken about two years ago by a Dunedin owner, who had since died.
Marsh spoke to the man's wife, and the car sales yard in Kaikorai Valley where it was sold, as he uncovered the scam.
He said he was given an address in Morrinsville to pick up the motorhome, but after checking with the city council there, found there was no such address.
"We cancelled the payment, the money didn't go through and we were very, very lucky," he said.
If the scammer had not changed the account, "it would have gone through".
"So we would have lost $17,000."
Marsh said he had also called a landline number the scammer had provided.
The names given were John and Barbara Stewart, but when he rang he spoke to a man with an Indian accent.
Marsh told him he wanted to look at the vehicle, but was told "no, no, no, you put the money in the bank and you can have a look".
He emailed and offered to fly up that day to view the vehicle, but got no response.
He said it was common to buy goods, even vehicles, online these days, and the sellers appeared legitimate.
An earlier email, supposedly from the Stewarts, showed the writer had limited English skills.
It said: "Please note that belongs to my brother-in-law, has seriously problems with his health now (speech & hearing impairment), so we have to manage the sale in his place (lonely and elderly guy of 79).
"I have power of attorney to enable me to sell it on his behalf, so you don't have to worry about that."
Attempts to contact the numbers used by the advertisers were unsuccessful yesterday.
Marsh has complained to police about the matter.
James Smith, of Allied Press, said the company had a system of checks with advertisements, and it was "very, very rare" for scams to get through to the newspaper.
Smith said newspapers were usually "far safer" than online in terms of advertisements.
As soon as the company was alerted to the issue the advertisements were pulled.
Buyers should always be aware of the possibility of scams, he said.
Ministry of Business, Innovation and Employment consumer protection manager Mark Hollingsworth said it was important to remember anyone could be targeted by scams.
Consumers needed to be vigilant.
"A good rule to remember is, if it seems suspicious or too good to be true, it probably is.
"The best way for consumers to protect themselves from scams is to be mindful and vigilant."
