Ktronics (PVT) LTD
Offgrid : You need followings items
02 100AMP deep cycle batteries -> 2 X 28,000
02 150W ploy chrome solar panels -> 2 X 14,000
02 20A PMW charger controllers -> 2 X 3,000 (if you can go for MPPT)
Without cables its only 90,000/= for 120 units.
Also those charger controllers has timers which can switch on load only after dark and switch off for given time period.
check out for projects done by Ktronics (PVT) LTD
https://www.facebook.com/KTronicsLanka. You can also visit those customers and see how there bill get reduces and the gains there getting.
Net metering : 1KW will be roughly 120,000/= after premises checked out it can be lower or may be higher depends on roof type, roof to meter distance, premises distance from our office, etc.