If you are talking about one that plugs into a household recepticle, don't think you will find any support for them there here.
I knoe every one wants to do things on the cheap, but man that ain't the way to go. Only time I'd even consider such a device is I had a off grid circuit with enough batery juice to support it
Just sticking it in to a reciptcle, might work ... every thing seems fine, then the power company gets wind of it, turns off your power. Or worse, you have a fire, and the insurance investigator discovers the unit, forget any help from them.