Australia's Tourist Refund Scheme can refund GST and wine equalisation tax on eligible goods taken out of the country. The threshold is not one AUD 300 item: it is at least AUD 300 including GST from one supplier with the same Australian Business Number.
Build the receipt before the airport
One shop can create several receipts
Purchases from the same business can be combined when the invoices show the same ABN. Two stores with similar names may operate under different ABNs, while several branches of one retailer may share one. The number on the invoice decides.
The sixty days run backward from departure
The goods must have been purchased within the 60 days before you leave. A long trip can therefore place early purchases outside the window even when they are still in your suitcase.
A digital receipt needs a physical audition
Australian Border Force says an electronic invoice must be printed for the claim. For invoices of AUD 1,000 or more, the invoice must also identify the buyer. Check that detail in the shop, where correcting it is easy.
Goods can claim; experiences cannot
Accommodation, tours, taxi fares, car rental and other services consumed in Australia are not eligible. The scheme is for goods exported with you. Items already fully consumed, including food and drink, cannot perform that final airport exit.
The final Australian port is the important one
If an international itinerary connects through another Australian airport, make the claim at the final point where you leave Australia. Goods that must be checked in may need to be sighted before baggage drop, so read the airport instructions and allow generous time.