It'd cost about $250-300 to ship to Australia, based on the last time I bought a laptop from the US. Then you pay customs & import taxes on the combined purchase+shipping costs, which would be about another $200-250.
It reminds me of my family from the UK when they used to travel to the US decades ago. They'd go home with half a dozen pairs of jeans each, and nearly pay for their tickets.
Shipping it to the US and then back might involve not only stupid expensive shipping, but also having to figure out paperwork for both Australian and US Customs, unless you want to potentially pay double import-duties on each side.
I did it with Lenovo laptops years ago, because buying from the US and with shipping it still worked out to be around 1/3 the price of buying it from the AU Lenovo store, and Lenovo had a Global warranty program on their Thinkpad line. Smaller OEMs without that, I wouldn't risk it.