https://www.bne.com.au/passenger/to-...nsport-options
Fare estimate
Passengers can expect to pay $45 - $55 (one way for a trip from the airport to Brisbane City). Outside of peak periods, it is approximately a 20 minute drive from the airport to the city.
Going further than the city? Use Yellow Cabs advanced fare estimator to calculate a fare.
And
https://www.taxifare.com.au/rates/australia/brisbane [BNE Fortitude Valley Station]
Estimated Fare $43.67 to $61.14
Distance 18.14 KM
Duration 21.60 mins
Also the train
https://www.airtrain.com.au/
On a Saturday traffic would be OK