There is a lot of sun here, and some wind.
Some heating needed in the coldest months.
Solar energy maybe. and even cheaper eould be clothing. take some off when you are hot. put some on when you are cold!
Although solar and wind energy are the cheapest sources of recurring energy needs. But the cost of setting up machines to convert these into electricity is high.
They have lots of ideas on green and renewable energy.
However, the best you can do (price wise) right now with today's techonolgy in Solar and wind is heating your hot water. Other than that, purchasing the power from the utiltity company is going to be your best bargain for the amount of electricity you need to fully power your home.
Solar is good, but the batteries are costly. I would suggest a combination of some passive solar with some wind turbines. For extra heat in the cold months you can always use wood-burning-stoves (more efficient than fireplaces).
Whatever you produce and do not use, the electric company has to buy back from you! Wouldn't it be great to be sending THEM bills, instead!
Cheap is relative. Solar is the cheapest (running cost-wise) but expensive to initially set up)
This depends on the local utility infrastructure, utility price levels, what you want to power and whether or not you're including up-front capital in your definition of the "cheapest."
Solar energy is cheap in areas of high sunlight, but very expensive in initial capital costs.
Electricity in certain areas (Kentucky) is very cheap due to the coal resources utilized by the utility companies.
Gas furnaces operate more efficiently than electric furnaces.
Architecture can also aid in decreasing utility bills through proper window design, etc.
To sum, it's an easy question with a difficult answer.
depends on where you live
most places, natural gas, propane, heating oil, or electricity is cheapest
thats why these are the most widely used
people don't deliberately use more expensive power
solar, wind, geothermal, and many other energy sources can sometimes be cost effective but usually are not, because of the high cost of the necessary equipment, or the unreliability of the sunshine, or many other reasons