* Verify ownership: They'll need proof you own the car.
* Program the key: For newer vehicles, this is complex; a 1993 Lumina is likely simpler, potentially just requiring cutting the key to the correct shape and possibly a simple programming procedure. However, the method varies depending on the vehicle's security system.
* Potentially replace the ignition switch or locks: In some cases, if the car's security system is compromised or the locks are damaged, replacement may be necessary. This would significantly increase the cost.
The best course of action is to contact your local Chevrolet dealer or a reputable locksmith specializing in automotive keys. Get quotes from multiple sources before making a decision. Be prepared to provide proof of ownership (title, registration, etc.).