This is my first time buying something outside of Australia so from what I'm understanding you have to pay GST for under $1000 since it no longer free.
Where do you pay the tax, to the courier? Also, if the sender declares it as a gift instead of business, then does it mean I don't need to pay GST?
In most cases you wont be charged it.
The ATO say that you'll be charged but the reality is that you wont.