What You Need to Know About Car Ignition Key Replacement Based on the type of key you have It will affect the cost to replace the key. Traditional metal keys with a blade which inserts into the ignition cylinder are less expensive. Flip keys, popular in the 1990s, include keys and fobs in one piece. These keys require a more intricate replacement procedure that can only be handled by professional locksmiths or dealerships for cars. Cost The cost to replace the ignition key for your car ignition switch repair varies depending on the type of key ignition replacement used and the model and make of your vehicle. Traditional keys that do not have transponders are the least expensive to replace. However, you might have to pay more for a key if you require a smart key, or key fob. The dealership is the most expensive option to get a replacement ignition key. This can be a time-consuming option, and it's not always practical.