I've put network gear on commercial airlines for a lot less money than it costs to ship something but never outside of the U.S. The company I work for is freaky about outsourcing anything having to do with programming network equipment so sometimes when a router or switch goes down, we have to program and ship on a commercial airline and have the manager of what ever office it is go to the airport and pick it up. I'll ship a router from NY to the West coast for $60. I'm not sure if this would work for you, but it's certainly worth looking into and it's easy to track for the buyer. If it even saves $100 it's worth it in my eyes.
Other than that, I'd have the buyer dump the $400 into your Paypal account and take a vacation to Australia. I've never heard one bad thing about Australia.
Other than that, I'd have the buyer dump the $400 into your Paypal account and take a vacation to Australia. I've never heard one bad thing about Australia.