Lost one airpod
How can I replace one AirPod and what is the cost
Question marked as
In the U.S., $69. Also see the following from If your AirPods are lost - Apple Support
If you still can't find your AirPod or Charging Case, or if something is damaged, contact Apple Support for a replacement. Then learn how to set up your replacement.
You can also learn more about AirPod pricing and service options.