Investigators released surveillance photos in the hopes someone will recognize the suspects, or their car.
That car is described as a white Nissan Altima model year 2010, 2011 or 2012.
Police say that car has a distinct dent under the driver's side door.
One of the businesses hit was the Hess Station on Street Road in Upper Southampton Township.
"He actually threw up a thing of Twizzlers and gave me a $20," said employee Todd Reiter. "It didn't feel like money."
"He hit it with the pen and it passed, but it still didn't feel right," Reiter continued.
So, he held it to the light only to discover the bill was missing its security bar. That's when he called police.
Reiter says he checks all the money to make sure it's real, saying it's his responsibility if the register comes up short.
Police say the problem with fake money is that once it gets passed around, it's in circulation and becomes a problem for everyone.
"We all count on the money that we have in our wallet being actual good currency to buy things but counterfeit money is completely worthless," said Richard Goldberg, the Economic Crimes Chief of the U.S. Attorney's Office.
Investigators say the pair have been seen using their money in Lower Moreland Township and in Dublin Township as well.
Anyone who recognizes the subjects or vehicle is asked to contact Det. Craig Rudisill at 215-364-5000 ext. 117 or firstname.lastname@example.org
For tips on how to detect counterfeit currency, visit SecretService.gov.