How do I replace a 1993 Buick Riviera ignition key?

Hi there, last year I purchased a used 1993 Buick Riviera from a dealer here in Bristol, and just recently the keys have gone missing. I have replacement keys for the trunk and doors, but without a special chip key I have no way to start the car. Is there any way I can get a replacement? If so, how much will it cost?|||The dealer should be able to cut you a new key using the VIN. It will be quite expensive, I had a key made for my Ford Focus, and it was like $130 or so. |||Contact a Buick dealership and they will be able to look up the vin number and replace the key for you. Hubby says the most it would cost would be around $25. . .just depends on the place.