I live over here but spend 2-3 months a year in Australia (oz, as they call it!)
It’s hard to know specifically what to tell you about plans over there without knowing what you need. They don’t have unlimited data plans and wifi is not NEARLY as available there as it is here - most bars / malls will not offer free wifi, for example.
I always get a prepaid SIM when I’m over with a local number and then let is die when I come home. For spends of up to $40 Australian ($30) per month, prepaid seems to offer the best value.
[Australian prepaid Plans]
Coverage is just as unrealiable there as it is here sometimes. Telstra seem to have the best network but the other 2 main phone companies Optus and Vodaphone seem to do OK in the city.
I usually get a Kogan SIM delivered to my brother in law’s house so it’s ready for me when I arrive.
Hope this helps.