[Severe Nitpick Mode]

Power companies bill for energy, not power. The energy unit used is the kilowatt-hour, and 8 cents per kW-h is about average for the US. Bear in mind that energy usage is not the only charge that power companies impose. Most also add on something which may be called a Fuel Delivery Charge or something similar, which can vary from a few cents to 10-12 cents or more per kilowatt-hour, and may have various price points, depending upon your electric usage.

[/Severe Nitpick Mode]

Sorry, those things drive me crazy. Like calling Kelvins "Degrees Kelvin". Arg!