The Garmin 480 now has some company in the TSO C145/146 arena.
Current Garmin GNS430/530 can be bought that are TSO C145/146 compliant. Garmin are performing upgrades on existing GNS430/530s for $US1,500 right now, one of mine is booked in with the factory on April 16. At current exchange rates, a new TSO C145/146 GNS 430 costs less than AUD8,000.
As I've said before, when I can buy one from Garmin, the time for Australia to think seriosly about low level ADS-B might have arrived.
I don't work for Garmin.