Lighting Help...

I'm going to be growing in a (very) small space, with about 4-6 plants in there, MAX.

What kind of lighting setup should I have, I don't have that big of a budget, but I'll definitely spend some more if it will guarantee a better harvest.

Any suggestions?

it depends on how small, what are the dimensions? sq feet? Heat will build up quick in small areas so you will need to vent, also what is your budget? An hps is the best light to get but how small are we talking here?