Cost of energy
I have lived off the grid for over 30 years and have all of the electrical toys, replace my batteries every 8 years or so, and HAVE NO MONTHLY BILLS. $1,250 for batteries divided by 8 years = $ 13.00 per month. Cheep enough for you.
Also, I have not suffered financial loss due to black outs and losing everything in my refrigerator or freezer.