A lesson in gullibility cost a Frederick County man almost $3,000 last month.

The 22-year-old Cannon Circle man is out $2,968 after being taken in an international Internet operation known as the Nigerian Net Scam.

Frederick County Sheriff’s Office Maj. Robert C. Eckman said the scam basically works like this:

“You have something expensive, like a vehicle or a horse, for sale. They contact you saying they’re a buyer. If you’re selling it for $1,000, they say, ‘We’ll send you a certified check for $5,000.’”

The “buyer” in the scam says because they live overseas, they will send a “shipper,” who they say lives locally, to pick up the item, Eckman said.

The seller is directed to deposit the certified check and use the money, beyond the cost of the item, to pay the shipper for sending the item overseas.

“You deposit the check in the bank, and the bank clears the check,” Eckman said. “The shipper doesn’t come by. They ask you to send the remainder back to them.”

The Frederick County man was selling a car online, Eckman said. He asked $800 for the 1989 Nissan, Sheriff’s Office Investigator Bob Dean said.

“They sent him a forged cashier’s check for $4,000, and he was supposed to send them back $2,800,” Dean said. “It cost $168 to send the money Western Union, so he’s out a total $2,968.”

The man reported the scam to the Frederick County Sheriff’s Office on Oct. 27. Dean said it is unlikely he will ever get his money back.

Investigators’ advice to avoid this situation is the same as it is for any other scam.

“If it sounds too good to be true, it probably is,” Dean said. “If you’ve got a car for $1,000 and someone is willing to send you a $5,000 check for it, it’s probably a scam.”