hm...

Mh - Metal Halide
CFL - Compact/Condensed Flourescent Light
HPS - High Pressure Sodium

Surround ur plant with mylar to reflect the light, and have the light shine directly above, and close enough to the plant so it gets alot of TLC (tender love and care), but not get scorched..

goin cheap, use a Fluorescent.. It gets the job done, but if ur lookin for real potency, get HPS, but they cost MONEY.. so use CFLs to save, until you have enough $$ to upgrade ur hardware..

Idk about the Mh, i'm using fluro's..