If your Mercedes-Benz key buttons are broken, you don't need to buy a new key. In most cases, you can simply replace just the key shell. You can purchase a new Mercedes-Benz key shell (eBay link) online.
Watch the video above or scroll down below to find step-by-step instructions. No programming is required when changing the Mercedes-Benz key fob battery.
How to change the battery on the Mercedes-Benz key? TRIANGLE Panic Button