Juli Clover, MacRumors:

After the one-year warranty has expired, Apple will charge a $69 fee for out-of-warranty service repairs. Battery service for AirPods that lose battery capacity is free during the one-year warranty period or $49 out of warranty.

If you lose or damage one of the AirPods or the charging case, Apple will charge $69 for a replacement, regardless of whether or not the AirPods are still under warranty. The pricing in Apple’s support document is U.S. pricing, and will vary based on country.

Interesting that the AirPods do not need to be replaced in pairs. Great technology.