I need to purchase a charging case for my airpod 3rd gen

Hey there chuong227,

We'd like to provide a link that has the details for replacing your AirPods 3rd gen charging case: AirPods Repair & Service.

Under 'How much will it cost?', you'd choose 'Other Damage' for the Service Type, and then 'AirPods Accessories' for the Product or Accessory. Then, the third drop-down box shows two different ones for your AirPods 3rd generation: Lightning charging case or the MagSafe charging case.

If you need more help with this, you can reach Apple Support here as they'll be able to help set up replacement of your case: Get Support.

Cheers!