as far as I know they dont need any light. You can get the cheapo fixtures so u can see them like I have for my fowlr but u def dont need any high powered MH or T5 lights or anything like that. Check your local craigslist for sweet deals, I bet u can find what u want for 10 bucks or less.
No special light is needed at all for the fish. If you want to get some good coraline algae (the purple stuff) growing on your live rock you are going to want at least some PC's or better yet some T5s though.
special lights are not needed but...keeping them on a schedual for daylight and night time is probably a smart idea especially if you have any nocturnal species.
Although color spectrums have been known to effect coloring in different species.