3 foot x 5 foot by 6 foot room lighting

i have an under stairs room in my bedroom bout 3 by 5 foot, how many plants could i get in there and what lighting could i use. im thinking of a 400w hps or it that just not enough? how much money as an estimate does a 400w and 600w lamp use a month on 12 12? comment away

Couple of links that should answer your questions.
https://www.rollitup.org/view.php?pg=faq&cmd=article&id=259
https://www.rollitup.org/indoor-growing/3284-power-consumption-light-cost.html

oki ive ordered a 600w hps, my room has no ventilation other than gaps around the door my cfl grows have been succesfull, will ventilation be a problem my hps will be far from my plants

You will need an exhaust out of the room to run that size light, it'll soon get hot in there.
Putting the HPS far from the plant will create more problems than it solves, it'll just make them stretch to be closer to the light.

hmm well im going to have to see first hand, wont the room stay cool with an oselating fan i cant have any extraction leaving the room as the dooris the only exit

You can try it, but please don't put plants in there. You have 90 cubic feet, I have 125 with a 600w HPS and it's enough to raise the temperature by 18 degrees c (32f) without my extractor fan running, and there's a 45w oscillating fan moving the air around.
Even if you raise the light, the room will still heat up if you're not getting rid of that heat somehow. A swamp cooler or ac would lower temps a bit but it's far easier and more efficient to move air rather than cool it.
That's ignoring the fact that if the plants fill the room, they'll soon deplete the co2 in there until growth stops. You could run co2 enrichment, which would allow your plants to tolerate higher temps, but co2 controllers aren't cheap.
Can't you extract out of the door? You could get some panda poly, have the door open say a foot, then staple the poly to the doorframe and fix some velcro to the other side so it laps over the side of the door, then make a hole in the bottom for an intake duct (with a light trap if necessary) and another at the top with a fan pulling air out, preferably ducted out of a window or somewhere.
I know it's a bit out there, and not very stealthy, but I have your plants best interests at heart.

i see, im going to have to think of something, im going to have to open the door or something, mybe if i put a sheet on the inside of the door to trap some of the light escaping but yet allowing the air to leave the room still may work, maybe the room a little higher than 6 foot but i can still see it may be a problem, i have 5 plant under cfls at the min and was going to put them under the hps. i got a possible problem then. i will let you know what the score is thanks for all your advice

Dude Id really listen to what hairy bob just said, its good advice and it wont ruin your door. Youre gonna have 90+ degree temps with that bulb in that grow space.

That light will make the room too hot to grow anything without an exhaust fan. It is a necessity and there is no way around it. If you want to grow weed you need to fork out the money to make it happen. I would get a 6 inch inline fan.

i have a 240 cf room well insulated and a 400w hps will raise the temp about 15 degrees f. absolutely need an exhaust with a passive intake. you may even need an air cooled hood or cooltube.

I agree about the air cooled hood also

Agreed, cooling the bulb really helps to keep temps in check. If you wanna do it right get an air cooled hood with a flat glass plate below the bulb, as cooltubes refract the light as it passes through the curved glass, diffusing it and resulting in less getting to the plants.
Also make a separate intake and exhaust for the light, and use insulated ducting after the light hood so none of the heat from the bulb gets to the room.