Like anything else relying on a battery, you car key fob can die—often at the worst time. Thankfully, these batteries are easy to replace.

But maybe you’ve experienced the downside: The cost to replace the latest key fobs can be as much as $400 depending on the brand. Then add another $20 to $130 to program it to work with your car.

In this primer on how to replace a car key fob, Consumer Reports says getting another high-tech key fob can be a pricey proposition.

Instead of using a key to turn the ignition or verifying your presence inside a car using a fob, the vehicle will communicate with your phone over Bluetooth.