Which GPS Tracker do you use?

What SIM do you put into it (if applicable)?

Does anyone use  a GPS Tracker in Australia?

If you mean find a lost drone GPS tracker, No. Any other type, Yes.
Rise above have Trackimo with sim and free GSM for 12 months at 160. Though if you are flying in an area without mobile coverage it may be useless? It would have to be some SPOT type service relying on satellites.
I would not get one for my P4. Cost verses benefits does not add up to me. Given all the new technology, double compass/GPS and firmware development, it is getting increasingly unlikely to lose one. If you had some $12K job, different matter.  

I would like to know as well, bit confusing without an Australian map to follow.

Im using Trackimo device, thought it will not require SIM to function but it has a very accurate tracking capabilities.

Looks like you will need the 3G version, as GSM is being shut down. Are there any that uses a beacon style tracker that is legal in Australia?

There's trackimo with their own world wide sim.