What are the cheapest lights to use? light info needed

I was sitting here and I'm working on a grow box of sorts
what are the cheapest lights to use?
what watts?
how many lights / watts for x amount of plants?
and how far do i put the lights from the plants?
if you can give me any advice it would be awesome my mouth is watering thinking about this box
thank you
-Highonbud

1. The cheapest lights to use are LED's.

2. The cheapest lights to buy are CFL'S.

3. The cheapest lights for "Most bang for the buck" are HID's.

alright thank you very much this will be very helpful on my stealth grow

The sun is the cheapest, and the best.

oh I know Colorado is a little bit on the shy side of great with the sun tho ... if it wasnt a stealth.
tho i might end up with solar panels just so i can use abit of the suns power to feed the lights growing my plants