Plug-in power monitor
Would you like to know how much energy your appliances at home are consuming?
This small but effective low cost device just plugs into any ordinary socket, and then plug your appliance into it. The device then supplies various readings regarding electricity consumption which may be used to calculate the electrical costs of the appliance.
One would be then able to accurately decide whether an old appliance is worth changing with a new one, or how much electricity does the idle LED on your TV waste overnight.