SAN ANTONIO -

Pulling up for a vehicle state inspection, an Official Inspection Station customer saw a sign that read, "State Inspections $14.50."

She said she was a little surprised when the technician charged her $21.

"It was just for the inspection," said the woman, who asked to be identified as "Ashley." "That's what I was there for. He didn't give me any other information. It was a very quick thing."

According to Ashley, the technician didn't offer any other services and, as far as she knows, he didn't perform any.

A week later, the Defenders sent a producer to the same OIS office on Culebra Road for an inspection.

After a quick glance at the receipt, the producer realized she had been charged $14.50 for the inspection, a $1 credit card convenience fee, a $1 shop fee, and a $4.50 Official Inspection Station service fee.

According to shop owner Charissa Barnes, the $4.50 OIS fee is for a package of services that includes checking the gas cap and topping off fluids.

While neither Ashley nor the Defenders' producer were told about this service or verbally given the option to decline it, Barnes said it is optional.

"It's a little misleading and ridiculous. Who would optionally want to pay an extra fee if they don't have to, other than if they sneak it in and you don't know about it?" Ashley said.

According to Department of Public Safety spokesman Tom Vinger, it is not legal to charge any service or shop fees over and above the $14.50 without advance consent from the customer.

He said DPS is investigating the shop.

Barnes said she plans to talk to the inspectors to be sure they are properly communicating with customers about the optional service.

She also explained that anyone who wants a refund can call the corporate office at 698-1000.

To file a formal complaint with DPS, you can call 210-531-2280.

For a list of recent stories April Molina has done, click here.