Paying $4 a gallon is already a lot, but you could be paying a lot more than that without evening knowing it.
"Essentially, what the criminals are doing is duplicating your credit card," said Watsonville Police Detective Charlie Bailey.
How? With a hidden skimming device.
"Skimming device is actually able to capture the credit card information as well as pin numbers," Bailey said.
The target? Those easy pay credit card machines on gas pumps. While cards are being swiped in Watsonville, purchases are being made with those card numbers in Southern California, police said.
Wastonvile police said it already has five reported victims and confiscated four devices.
Watsonville police said this problem is on the rise and it's been an issue in the Bay Area for several years.
"These are sophisticated criminals, they're picking locations that they know aren't monitored by surveillance cameras," Bailey said.
At Gomez Gasoline and Automotive, I recognized one of the skimming devices inside when the owner opened up one of the pumps.
We checked every pump and they all looked the same.
I called and told Detective Bailey that I found what looked like the skimming device he showed me at the police station.
When Bailey showed up, he confirmed it was one of the devices and quickly booked it into evidence.
Bailey said criminals will either physically remove the card reader or download the information via bluetooth to get customers' card numbers.
"Charges range anywhere from $60 to $150," Bailey said.
Although gas customers at Gomez Automotive used the pump with the device all day, the owner wasn't phased.
"I'm not nervous or scared," Adan Gomez-Hernandez said.
Bailey said he plans to assemble a team of officers to check every gas station in Watsonville.
As of Thursday, no arrests have been made.