With rebates, in my state it's about $1,000 per KW installed...$1,200 if you buy the "premium" kit.
Wholesale generation rates are about 4c/KWhr, retail about 27c, and the incentives for the early adopters were 60c/KWhr feed in tarrif. 500MW p.a. started getting put on roofs, displacing a coal unit every year...
There's a problem in that the panels were supposed to be offset from true north to provide peak load closer to evening peak, while the installers maximised daily KWhr (and certified their own installs)...there was talk about making them redo them to the planned angle, but they won't.
Now the feed in tarriff is the wholesale cost (4c), and people are whining about being ripped off by not getting parity with their retail rate.
Next big thing will be batteries, and people will be storing their own energy to use around the clock. I know a guy who did that $30k for a whole house install. His house, choice, and money, and he's a year or two from retirement, and considers the lack of outgoings in his retirement to be worth it.
My mother has a system that her and Dad sized to meet their reverse cycle air conditioning/heating load...they thought air conditioning a luxury all their lives, and put in a set of panels with their air-con as a single capital investment. Made them happy.
Another workmate on his way to retirement (guy shoulda been an engineer) knew that he and his wife would be home every day, so instead of facing his panels due North, placed 1/3 to get the morning sun, and the 2/3 to get the afternoon (with low sun angle in winter)...his is pumping enough at breakfast time to run their place. 11AM will run the aircon and clothes washer/drier, and enough to get the house cold all through the day. He's happy with his design, and how it runs his house.
Tax office is now all over "negative" energy bills as an income stream, and for retirees it's serious, so the engineered systems make more sense if used.
Emerging issue is that a lot of the inverters and whatnot are 10+ years old now, and the occasional failure is leaving rooftop panels a stranded ornaments because the replacement isn't subsidised like the installation was.