Please rely off list to my request.

I am in need of an electrical cost calculator - a box of some type that
will give me a digital readout of electrical power consumption and total
cost in dollars of cents for power consumed. Obviously this will need to
be programmable for cost per kilowatt to readout in dollars. I need to
plug a piece of equipment into the box and get a readout for each total
operating period of the equipment.

Anyone know of these things - or where I might look - or how I might build.

Please respond off list.

Thanks.

John