Transponder keys – Expect to pay anywhere from $100 to $250 for a transponder key replacement. The immobilizer chip in the key will also need to be programmed. Smart keys – Replacement costs for smart keys can range from $200 to $500 or more. The advanced technology and keyless features contribute to the higher price.

Generally, smart keys are worth the most money. The corresponding vehicle year, make, and model also have an impact on the value. Prices operate on the principle of supply and demand. If your key fob is rare or the buyer has not seen one in a while, you may get a better price.

It is possible, but not for all types of keys. It won't work with the traditional mechanical key. If you have a key fob, smart key, or transponder key, you can track them. You will need a car key tracking device or an app connected to your key.

The Serenity line comes with more than 20 carats of diamonds and 175 grams of gold. It will cost approximately $90,000. The Phantom cost nearly $600,000, making it the most expensive car key in the world.