It's a story that can help you save thousands of dollars.  It begins with a check in the mail but its ending depends on you knowing what to do with it.

“I had no idea who would be sending that money. I wasn’t expecting any money, so I got real nervous,” said college Robie Thacker.

That was her reaction when a $3,500 check arrived at her house, with no letter included.  A few says earlier, in the process of applying for a job on Craig's List, Robbie, who is a struggling college student, included her mailing address and email.

“I got a text message two days later saying I got the job,” she said.

Then came the envelope with the check.  She went directly to the bank.

Thacker explained, "They looked at it and said ‘I believe this is a fraudulent check’.”

“They’ll typically tell you to deposit the funds into your account and then wire some of the money back.” said US Postal Inspector Michael Romano.

If she had done that, Thacker said, “I would have been responsible for the entire amount.”

“No one you don’t know out of the blue, no one, will send you money. It just does not happen,” explained Romano.

Thacker's advice, "Don’t ever cash a check you’re not expecting, because it can really come back and hurt you.”

Postal Inspectors say there are several variations to this scam. Sometimes a check will arrive with a letter, claiming you have been chosen as a mystery shopper, and directing you to shop at certain stores. Sometimes victims receive a fake money order. If you can see Ben Franklin’s head without holding the money order up to the light, it’s a fake.