Ms Mathers said the rise of scammers on the Meta platform had been astronomical.

"As of a year ago, any time I post something straight away five scammers will message me," she said.

"And it's always the same, 'is this available?', 'what condition is this in?' and then something like 'I'm out of town but my son will come and get it, I'll use Pay ID'."

Ms Mathers recently fell victim to a scam when her partner attempted to buy a drone from the service for $1000.

She said the seller's profile came across as legitimate, although found it strange that they wanted to communicate via email.

"But his emails came from a company email, he said he was selling the drone because he didn't need it for his photography anymore. The ABN was registered so my partner transferred the money and then the person blocked him," she said.

"The scammer had sent through a registered post tracker but he never received anything. I can see why he thought it was legit."

About 17 per cent of people on the platform have been targeted by scammers with six fake ads posted to the service every minute.

Despite this, Marketplace is as big as its ever been, surpassing one billion users in 2021.

Proofpoint senior director Adrian Covich said the growing number of scams was the result of the service's popularity.

"The scale, the amount of people it reaches and the ease of use that it provides, it's not surprising to see that attackers are paying attention and trying to make the most of it," he said.

The most common fraud aimed at vendors is the Pay ID scam, which starts fairly innocuously when a scammer poses as an interested buyer.

"A really interesting red flag that's pretty common is that the person won't haggle for the price," Mr Covich said.

"They'll try to get you to set up a Pay ID account. Sometimes they use this old trick where they'll overpay you and then ask you to refund them.

"For example, if an item was $100, they'll pay you $120 and ask for the $20 back. In reality they've never sent you anything and you're out of 20 bucks."

Mr Covich said overpayment scams have existed for a long time.

"The oldest one was to say 'I've got a check for $10,000, if you give me $2000 we can split the difference'. This is just a new manifestation of that," he said.

Users were less wary than they should be, he said.

"There's a whole bunch of people who are going into this thinking it's the same as buying from a shop online, and it's not," he said.

"Attackers know they get access to a lot of innocent people via these bigger marketplaces."

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Mr Covich said users should always look at the buyer or seller's profile before going ahead with a deal.

"Try and check their bona fides if you can. Do they look like a real person with a history of buying or selling or at least a history on the site?" he said.

Buyers should be aware of their personal safety.

"There's a physical aspect of being careful about where you share the goods.

"So you're not meeting someone in a place that you wouldn't meet a stranger, particularly if you're turning up with money. I would advise taking someone with you if it's a particularly big purchase," Mr Covich said.

"Any sort of payment scheme that you're not comfortable with where you're giving out your credit card details, be very wary of those.

"The biggest thing is just to have your wits about you. If it's too good to be true, it usually is."

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