WGN Investigates a financial scam that’s been around for years and continues to grow.

Experts say people are especially vulnerable this time of year, tempted by the offer to act as a “secret shopper” in exchange for extra cash.

“Who doesn’t want to go shopping and make a little money,” Lisa Bates, of Chicago, tells WGN Investigates.

Bates recently received an unsolicited “priority mail” envelope with a check inside for $2,450. The sender claimed to be offering a cash advance for help evaluating retail gift cards.

The letter asked Bates to deposit the check, then purchase $2,000 worth of gift cards within 24 hours. She was then told to scratch off a code on the back of the card and send a picture to a cell phone number, giving the scammer access to the gift card.

She didn’t fall for it but others have.

The Better Business Bureau’s “scam tracker” has logged more than 100 reports about these fake check scams in recent years. Nationally, it’s the second most common complaint to the BBB. People in their 20s are the most frequent victims.

People often get fooled because banks credit your account before the check clears.

By the time, the error is discovered your $2,000 is gone and the scammers have spent the gift cards.