If you have a kill a watt thingy you can see it before the bill comes up but basically, when you start mining if you consume 100 W/h more than
100 x 24 x 30 = 72000 W = 72 kW
let's say electricity in your country costs $0.1 kW/h
it should cost you about $7 if I'm not missing anything.

so tell me what this bitcoal thing!!11 jk.