Well here is the thing my roommate is making a huge fuss about me having a 75 gallon fish tank

and our bill going up, he seems to forget were in the middle of summer with the a/c going, anyways i want to settle this by finding about about how much extra i should pitch in to our electricity bill.
I have an:
Air pump = 3.5 watts (runs 24 hour)
Filter = 11 watts (runs 24 hours)
Lamp = 67 watts (about 4 hours a day)
Heater = 200 watts (which stays on for about 2 minutes and turns on every 7 minutes)
now i understand every location charges different amounts on electricity
but how much am i looking at? also can u include the formula so i can add the price per watt once i find out how much it exactly is...
thanks for the help