if all you want is one plant/personal consumption, 600w or even 400w is silly, especially if you "would like to spend as little as possible". you can buy 42w cfls for under $10 here in the you-ess and pick up fixtures for them at home despot for about the same... say $25 for both on a bad day. if you buy 6 (more than you need for a single plant unless you let it get out of bounds - cfls work well with SCROG and LST) thats $150 for about 250 watts.

AND you have way fewer problems with heat/ventilation.

q