[Possibly limited to just Canberra and for VDSL2 service]
iinet appears to have their 75/20 for $40/mth for 12mths no-contract at a qualifying address. Not sure which service mix and locations but my fttn address works. (ie unsure if limited by location or if service provider POI is still a thing).
Minimum cost is $110 due to $60 setup fee and $10 for hardware delivery (creates a future return / payment obligation).
You may be able to avoid that and the $10 charge if you can request / convince them modem is not required.
May want to add this is VDSL2 not NBN