Just because it's made about the same distance means nothing; US recieves discounts because:
A. It's designed here.
B. We order a SHITLOAD to cover the various regions.
Wheras you have Austrailia, which, no offense, is much smaller and has had less experiance screwing with the technology ;)...
Not to mention, I use newegg due to the prices, at most other places, that $150 500gb hard drive would be $300+