figuring out my kilowatt usage?

so i recently completed my first closet grow with moderate success but got some less then enthusiastic responses from my roommates about thier CUT from us all sharing electric bill .... im starting again an want to try to figure out HOW MUCH IM ACTUALLY SPENDING ON THE grow in KwH per month?

ive read a some examples of how to figure it out on paper and think ive figured out my monthly usage of the cfls because i know the wattage, but now im trying to figure out how much power is being consumed by my lakewood 12" fan, 80 cfm broan vent fan, and a little pollinex "pure aire 99 " air filter/deodorizer (little fan in plastic housing)???

ive also seen the KILL A WATT usage meters but when unemployed and losing benifits soon i'd rather not spend the extra money ...


ANY SUGGESTIONS? ...