It happened around 8 p.m. Sunday when police responded to the store on Miles Road.
According to police, suspects walked in with the fake cash in exchange for a deposit on their Cash App.
"They have the app on their phone, pharmacy scans the barcode to their Cash App, it registers how much they want -- $100, $200 whatever. You pay the cashier $200, and once the transaction is complete, it goes on your app," said West Chester Police Public Information Officer Dave March.
Investigators released surveillance images of the suspects on Monday, hoping that the public can help them identify the men caught on camera.
Authorities are also looking into whether this incident may be connected to a counterfeit bills case in Kennett Square.
Police there say on May 30, at approximately 9:15 p.m., two men passed a fake $100 bill at the Star Gas & Diesel on Cypress Street.
Authorities said the store owner reported seeing the men in that case a few weeks before, but recognized the scheme and confiscated the bill in the first instance.
Kennett Square police have also released surveillance images of those suspects, hoping the public can aid in identifying them.
The U.S. Secret Service seized nearly $22 million in counterfeit cash last year.
In May 2023, Philadelphia Customs and Border Patrol officers worked with the Secret Service to seize more than $14 million in counterfeit currency from several multi-million-dollar counterfeit smuggling attempts.
The Secret Service says to pay attention to items like the watermark, shifting ink, and serial numbers on bills.
Police say it's important business owners and consumers both know how to spot fraudulent money.
"They could go to a store and get it as change or go to the bank and get it as change," March said.
These local cases may only amount to a few hundred dollars, but police want the fake money and those who pass it off the street.
Anyone with information on these incidents should contact the police.