I need to return an Amazon Kindle to the USA. Lithium batteries are restricted by NZ Post, and can only be sent using the express international courier, with the proper form filled out and attached. That will cost about NZ$105 to ship, which is what the kindle is worth.

Is there any more economic way to return a Kindle to the USA?

I checked packsend.co.nz, which is $67 for their economy service, but that automatic quote doesn't take into account it's a lithium battery. I think they need to pack it themselves so price would be about the same as NZ Post.