All carriers in Australia are much of a muchness.
If you already have a phone (unlocked) you can purchase a cheap sim card at the airport (directly next to arrivals gate) as well as a dongle. My choice is Optus for both, better range (in all areas) and affordable. I have a pre paid phone and buy $30 worth of credit per month which gives me $300 worth of calls, sms's and unlimited data on social media. To date I have never run out of credit before the month is up.
To be absolutely honest, I have had more problems with range on my old Telstra plan than I have on Optus, even in the middle of the CBD. over 7 years ago
If your phone is unlocked, get a prepaid AMAYSIM sim (available from most supermarkets and phone shops). It uses the Optus network but is a quarter the price for calls, text and data. I changed over about 6 months ago and have never regretted it. over 7 years agoAnswered by John W. via WorldNomads.com
telstra with an iPhone 4S forrrr da win over 7 years agoAnswered by k-dawg bring' in da monaaay via Travellr.com
regarding calling here, if you need to call to outside Australia like me, one cheap and good way to do it is using the Global Call app. I've been using skype but it gets too expensive so I switched to Global Call, which is cheaper and they give free credits usually. Just want to share with you about a new convenient way to call abroad from Australia almost 6 years ago