See my previous posts regarding duty and gst. Basically if you get it sent via USPS and the all up total including freight is less than $500AUD you wont be slugged. If it comes via any of the express couriers the limit is $250Aud. I actually rang customs to confirm this some months back and have bought a few items from the US via USPS and only got clipped once when the total was $517AUD. Didnt do my maths properly and paid for it.