Gone are when you couldn't start your car's engine without a physical key. Modern vehicles today come with key fobs that are more useful than just starting your car and locking and unlocking its doors ...

Your key fob contains a hidden mechanical key blade that unlocks your car when the battery dies, plus backup engine start procedures.

To better understand the steps needed to replace a key fob—and the costs—we set out to buy and program several of them. Along the way we learned several valuable lessons that can help you save money ...