One of the main problems with pricing standalone power systems is that it is impossible to do until the system is at it’s end of life.
My first LiFePO4 system cost just over $35k for a 400ah 48V pack, inverter, PV and CC, cables and back up generator.
It has been averaging 15kwh/day throughput for 8 years, which puts it’s cost at around 72c/kwh.
Obviously the first kwh cost $35k, the first 2 kwh cost $17.5k each and so on.
That system may last 20 years, or it may have a catastrophic failure tomorrow.
Cheap batteries are great, batteries that will return the greatest kwh/$ are what i’m looking for - unfortunately this figure is a guess based on the life of similar batteries.