Many of us are heading overseas and there is a standard PCR test requirement within 72 hours with proper test results instead of just SMS, for most airlines.
For Sydney, the cheapest options is via Histopath @ $100, done at airport on the previous day (considering your flight is after noon as the results will be available only at 9 am next day).
Next cheapest is 4cyte at $120
Edit:
Looks like there are other locations which offers $100 tests.
* Granville as per @DaddyJi
@initiateit: well I am from Queensland so Zero cases is the norm, can't speak for other states. cough nsw, cough VIC….. Opening up internation travel just mean you open up the country for a whole of hurt there are strains of the virus out there that are worse than delta where the vax doesn't work at all.