BROKEN ARROW, Oklahoma - A Broken Arrow woman has a warning about counterfeit money being passed at garage sales.

Police said it's not the first time it's happened, and you need to be aware of it.

When Lisa Kirkley had her garage sale, she knew not to accept checks and to be leery of $100 bills, but she never dreamed it would be a $20 bill that was counterfeit.

"I was like, ‘Really? It's a garage sale.’ They probably bought a 50 cent item and gave me the $20 bill. I'm thinking, ‘What a way to make a living,’" Kirkley said.

Summer time is garage sale time, and lots of people are selling their old things to make a little extra money and clear out the clutter, and shoppers love getting a bargain.

Police say criminals see garage sales as the perfect place to pass counterfeit money because things are hectic and people are trusting.

Kirkley said, "50 or 60 dollars was the most expensive thing we sold."

She pulled out some of her garage sale money to give to her cleaning lady, who later went to QuikTrip to buy gas.

"She handed them one of the 20s and, at that point, they said ‘this is counterfeit,’" Kirkley said.

Once she got it back and put it next to a real 20, she could see the ink was darker, the paper didn't feel quite right and there was no watermark.

So, she posted about it at nextdoor.com - a website that keeps neighbors informed of everything happening - and learned she wasn't the only one.

"Others in the neighborhood had been given counterfeit 20s in their garage sale," Kirkley said.

Police say the best way to protect yourself is to use the counterfeit pen to check all your 20s, or post a sign saying you'll only take 5s and 10s.