Just as a hint. Make sure whatever devices you get a 3g/4g/M1 capable.
The last 2G network in AU shuts down 31 March 2018(vodafone)
I bought several dev modules to play around with and because of my own lack of reading realised that they won't work come the shut down.
Telstra launched their Cat-M1 last month so devices that use Cat-M1 will be the best long-term device.