You can't buy AirPods with only one AirPod from Apple's website directly. However, you can either: contact Apple Support on the Apple website and ask to buy a single AirPod and case, or you can buy them with both AirPods then sell the one you don't need.
What if I lost 1 AirPod?
If your AirPods or Charging Case get damaged accidentally, you can replace the damaged item for an out-of-warranty fee. If you lose an AirPod or your Charging Case, we can replace your lost item for a fee.
Can you find a single lost AirPod?
You can easily find your AirPods using the Find My app on your iPhone or by visiting iCloud.com. You'll see where your AirPods last connected to your phone. And you can even ring individual AirPods if you're just missing one.
How much is a single AirPod?
AirPods AppleCare+ fee (each incident) Out-of-warranty fee
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AirPods $ 39 $ 95 each
Charging Case $ 39 $ 79
Wireless Charging Case $ 39 $ 95
MagSafe Charging Case $ 39 $ 95