Counterfeit money orders are at the heart of this scam.  It starts with victims responding to a job ad that says, "Receive money orders like these in the mail - then go shopping."

"They would go to Walmart, make purchases, rate their service they received at Walmart, then they would go back to western union and mail back the remaining money to suspect," explained U.S. Postal Inspector David Nitz.

After following those instructions, the victims would get a surprise.  The money orders they deposited into their bank accounts were counterfeit and they would be in a situation to repay that to the bank.

Postal inspectors were tipped off to one recent case after customs intercepted a package containing $400,000 worth of counterfeit money orders.

"After making contact with this suspect, did a search of her home and found $300,000 worth of money orders," said Nitz.

In this specific scheme, there was 750 victims and more than $300,000 in losses.  Inspectors say the scam is on the rise and targeting vulnerable victims.

"A lot of victims are already in financial distress," warned Nitz. "To get involved in something like this just compounds the problem."

Nitz has advice for anyone looking to make money this way.

"Don't get involved in something that was unsolicited," he said. "Somebody sends you money orders or checks and you don't personally know them or haven't been personally doing business with them you shouldn't be cashing those checks."

Postal inspectors say if you ever want to verify if a money order is "real" you can take it to a post office, employees have been trained to detect counterfeits.

Also, call the Better Business Bureau to check out any business that tries to solicit you. The phone number to the Better Business Bureau of Northeast Florida is (904) 721-2288. 

Finally, never send money back to anyone who sends you a check or money order unless you know exactly who they are and you're certain they are legitimate.