since there's a nabi customization store, is the avatar size you buy permanent?
Also who do I buy it from?

With purchases of larger avatars or usertitle images etc you have to provide an image. That image is what is used in the customisation. You won't be able to change to a different avatar of the same size later, it will revert to your usergroup default.

So if you never change your avatar after buying it then yes, it's permanent.

Alright, thank you, closing thread.