Approximately one in every 25 previously deployed airbags is replaced with a nonworking system, dummy airbag or trash, according to Carfax, a provider of used vehicle information.Replacement airbags can cost anywhere from $2,500 to $3,000 a piece. But crooked repair shops can pocket insurance claims for replacing them, according to a report in Driving Today. Crooks will actually installing a dummy system that simply looks like an airbag. When they do an improper repair, they are actually pocketing the money and putting unsuspecting consumers at risk.Experts say if you're buying a used car, you should first get it checked out by a mechanic you trust. Only a mechanic can make sure your airbag system is functioning properly, the Driving Today report said.