South Philadelphia 7-Eleven store owner Vincent Emmanuel said it's like the Grinch that has struck his shop time and time again.
"These bills look so good, it's even better than the real ones," said Emmanuel.
Over the last few days, Emmanuel's store got burned by schemers who used several thousand dollars of fake bills to buy pre-paid Visa and MasterCards.
"And the clerk behind the counter is always busy. By the time the person realizes that it's a fake bill, the person is out the door," said Emmanuel.
And he is not alone.
Authorities report that a number of businesses have been hit by the bogus $100 bills and other counterfeit money, as well.
The counterfeiters have also figured out how to avoid detection by the marker pens that show whether a bill is fake or not.
"Sometimes they bleach the $1 bill and they print $5 or $20 on top of that and when you use the pen, it doesn't work, it shows that its good currency," said Emmanuel.
But now, those behind the latest fake $100 bills may be using an all-new technology: 3D printers.
"You gotta check that $100 bill, check that $50 bill, check that $20 bill because this is the holiday season, you can't do nothing but be extra careful," Emmanuel said.
The Secret Service estimates roughly $50,000 in counterfeit money is passed weekly through the Philadelphia region.
If there is any question as to whether the currency you have is genuine, contact your bank or local Secret Service office.
The Secret Service shares these tips to help you spot fake cash.