In Georgia most insurance companies use what is called an indexing service. This is a service that will take your zip code and then contact car dealerships and cars for sale near your zip code and as close to the exact make and model of your car. After obtaining as many cars as possible they will average the cost and that is usually how they come up with their values.
While these indexing services are available to you, you have to pay for their reports and most people do not wish to do so.
If you want to get an idea of the value knowing that it may not be exact, a good source is to contact the online value services such as Kelly Blue Book, or N.A.D.A., their valuations will be quite different and some will ask for more detailed options. This will provide you with a source to estimate the value of your vehicle. Please keep in mind the value of your vehicle often does not correlate with what you may owe on the vehicle.
Most people believe that the insurance company must pay off your vehicle, this is a myth. The insurance company only has to pay the fair market value of your vehicle and different things like mileage and condition can have an impact on the value.
My office always gets the questions from people what if I do not wish to accept the value of the vehicle the insurance company wants to pay. Well the first thing to understand is you have options but they often take time. The insurance company is not required to provide you a rental car while you work out your difference with them, they do not have to pay for a rental vehicle after they have determined if the car is repairable or if it is a total loss or not repairable.
You always have the option to take them to court, but you have to prove that your value is the real value and often that will require a professional estimate which cost money that you may or may not be reimbursed for. In addition, when you file a law suit you will have to pay to file the complaint and serve the defendant. If any of these items are a problem it can delay your resolution of the property damage.