I bought a used 1999 grand prix gtp, and i believe there is a pre installed security system but i didn't recieve any FOB's with the car. What is the cheapest way to get new FOB's and to go about having them work with my car? I do not know much about cars, but can read directions. The manual says to go to the dealership, but I know that can get very expensive. Any help would be great! Thank you!