"These are not real bills. Whether it is a laser jet or an ink jet, these are just on decent paper," he said.
Police say quick transactions, such as those at a counter, make it easy for counterfeiters to pass off the fake money.
The fake $10 bills are the latest in a string of counterfeit crimes in Polk County this summer. Last month, a pink-haired suspect was caught on surveillance cameras in Winter Haven passing fake $50 bills to at least six businesses.
"People like to come this way, commit their crimes and then leave because of anonymity," Black said.