A secret shopper scam is no mystery to a Virginia man, and he is reaching out to warn consumers before they get ripped off, WWBT reported.

Brad Beatty said he was sent a priority overnight envelope containing a $2,900 cashiers check. The note in the letter congratulated him for being selected for Secret Shopper, a program that rewards shoppers for spending the money and then sending in a survey about experience.

As Beatty warns, there is no such thing as free cash.

“Nobody is going to send you $2,900 to do them a favor,” Beatty told WWBT. “They're making you feel like you're doing a deal and getting paid for it, but you're not, because they're going to take that money right away.

“When the bank finds that the check is (a) fraud, they're going to take it out of your savings, and you're out of the money.”

The letter instructed Beatty to keep $400 and use $2,500 to buy five $500 Walmart gift cards, WWBT reported. Then he was told to take a picture of those cards, peel the silver scratch-off from the back, and then email the photos along with a survey about his shopping experience.

Beatty said he received a text message that said he would receive a $100 bonus if he completed his assignment in a certain time frame. He said he was not sure how someone got his mailing address and cellphone number, but added that he has been contacted several time since the envelope showed up at his home.

“If they give out 10,000. I bet 50 to 100 people will do it and lose money,” Beatty told WWBT. “I don't want to see anyone lose their money”

A search on the Better Business Bureau's scam tracker shows there have been 750 reported "Secret Shopper" scams in the United States. On Walmart's website, there is a page dedicated to Fraud Alerts -- one of them warns against mystery shoppers. Walmart says it doesn't "utilize these services or hire associates to perform services on behalf of other retailers or companies."

Beatty preaches caution.

“Just be very careful and check things out before you go cashing checks,” he told WWBT.