REPORTED cases of online auction and shopping scams have doubled in the past year, forcing trusted companies to issue urgent warnings to customers.
Online auction scams have become the second most common type of fraud reported to the Australian Competition and Consumer Commission.
The Trading Post was forced to issue a warning recently after a large number of users reported being contacted via SMS with money transfer scams. eBay and Carsguide users have also been targeted.
While details vary, sellers are usually contacted by someone claiming to be interstate or overseas who wants to buy an item unseen.
The scam artist then sends a fake email statement from a financial institution such as PayPal, saying the funds have been paid but won't be released until a fee is received by the buyer's "shipping agent".
Unley Park resident Lucy Jones tried to sell her van online and only narrowly avoided being conned by a scam artist posing as an oil rig worker.
She agreed to sell the vehicle but became suspicious after receiving a poorly formatted email purporting to be from PayPal and requiring her to pay shipping fees via money transfer company Western Union. Ms Jones checked with PayPal and discovered the email was fake.
"I'm a very trusting person and I really wanted to sell the car," she said.
"If that email had been set out a little more professionally they probably would have got me - I think it was a very close call."
The Advertiser was contacted by a scam artist within minutes of posting an advertisement online to sell a $2000 car.
In an email correspondence the scam artist offered to buy the car unseen but required a payment be made to ship it to the United Kingdom.
Another SMS, attempting the same con, was received a few hours later.
Trading Post communications manager Lucinda Tippett warned users not to use money transfer services like Western Union, and to beware of buyers from overseas and those who only communicated via email.
"It's a confidence scam and is often conducted by international fraudsters," she said.
Consumer Affairs Minister Gail Gago said buyers and sellers needed to be "extremely cautious" online and "do as many checks as possible" to ensure the deal is genuine.