My bad KlaPeck... I calculated it wrong... Use this site.

http://www.electricity-usage.com/Electricity-Usage-Calculator.aspx?Device=&Watts=850&CostPerKWH=0.10&HoursPerDay=24


But also take into consideration.... you arent using the full 850 watts. Watts = Volts x amps

Ohms Law

If you are in the US Volts is 120 on standard outlet

http://www.angelfire.com/pa/baconbacon/page2.html

With the Amps i gave you.. At full load you are using 648 watts.

So you are looking at $43.55 per month.