Lots of stuff to digest here. Here are a few very rough numbers that will get you started:
1. Figure $1.00 per Watt for panels (parts only)
2. Figure $1.00 per Watt to install the panels, including the inverter and transfer switch
3. Figure $1.00 per Watt-Hour for battery storage (labor cost is relatively minor for the battery)
4. For power production, figure an average of 5 hours of production per day (but varies depending on local climate/latitude). Assumes no shading and decent pointing.
So, for a large 10 kW system with 18 kWh of battery backup, $38k ($10k + $10k +$18k) would be a reasonable cost (before rebates, of course).
With that you’ll get around 50 kWh per day, or about 2 kW steady, which should be enough for non-AC loads.
As to payback, if you are interested, the big variable is the marginal cost of power, which can vary from 10 cents per kWh (Texas) to 30+ cents per kWh (California). For the above example, in Texas, you generate $1800 per year, so 21 year payback. For California, you generate $5400 per year, so 7 year payback. So big difference, depending on rates.
Oh yea, the 26% tax credit will shorten the payback time significantly for all cases (net cost $28k) - so 16 years and 5 years for the above, although sales tax on the parts will offset some of that savings.
$1 watt for bulk panels??? You are getting ripped off. There are literally hundreds of suppliers with 300 to 550 watt panels for 13 to 28 cents per watt.
https://m.alibaba.com/product/1600383259141/Solar-Cell-FUSOLI-Solar-Mono-Solar.html