i have something very similar - it comes in the mail every month with out fail - its called a bill

These may not be for everyone, but they can help you lower your monthly bill by showing which appliance uses more electricity. A bill can not do that.

For example if you have a block heater for your truck this will let you measure how much electricity was used overnight that you might know how much it costs.

If someone at work insists on keeping a space heater under their desk, this will let you show how much it costs.

If you leave your computer on 24/7, this will let you see how much that costs.

Meritline has these on sale for cheaper today. see here: http://www.meritline.com/dailydeals.aspx?source=nl100423&hq_e=el&hq_m=1952165&hq_l=2&hq_v=fe27daca98