L
uckily, it is going to be nowhere near what Leadsled T28(and his other guises) and Smith and another identity from your way, predicted.
Oz, old mate,
For a start, I am not T28, in the whole history of pprune, I have had one, and one only, identity.
As to prices for COMPLIANT ADS-B in Australia, the Garmin 330 Mode S transponder is the only "low price" one available (so far) that meets the standards (and not temporary concessions that apply to most AU present equipment) you can look up the price (make certain you use the correct 330, not the base model price), plus the price of a compatible C145 or C146 GPS, plus the cost of installation.
It is considerably cheaper in the US, because a top of the line Mode S transponder is not required, just a UAT set connected to (if one isn't already on board) C145/146 GPS source.
A number of apparently dirt cheap European sourced 1090ES transponders have been promoted on pprune, last time I noticed, another one has already gone broke.
A price check for the Garmin 330, of the model required for ADS-B, plus the GDL 90 as a GPS source is around US $10-12,000 just for the boxes,(US price, there are some hefty margins added here, plus GST) plus however long to fit at about AUD$150 per hour, and this just for ADS-B Out ---- about AUD $19,000+ , this includes no displays of any kind in the cockpit.
All this for a simple GA installation, if you have any of the newer "glass cockpit" aeroplanes, it's model specific, and not cheap.
Of course, FAA aren't into "mandatory for all" mode, that we seem to be so good at here, GA has the choice of UAT, which is cheap.
Tootle pip!!