Decent solar systems start right around one thousand more or less. However, consider gas, though dropping is still "ABOUT" 4.00/GALLON, My Onan 5500 sucks about 0.3 GPH, at full load 1.3GPH, so figure 4.00/hr to run
250 hours, that is 12 days full time, About a month as we use generators. You have recovered your kilobuck
And what's more.. You never ran out of gas