The only corals I would hesitate with would be SPS
ones. Although placement is also key as well as the actual light.
You would be able to keep all softies and LPS
corals with 4 bulbs. You get into the grey area when you want clams, SPS
and anemones. I kept SPS
under 4 bulbs and it did pretty well but I had it higher up in the tank.
Here are two sites you might wanna look at for cheap lights:
fish need it;lights; food;Sponge
Aquatraders - Guaranteed Best Prices on Aquarium Lightings + Free Shipping!
Both have decent fixtures for around $100 that have 4 bulbs. The aquatraders ones have led
moonlights and timers and the fish needit light does not. I currently have 2 from aquatraders and one fixture from fish needit and they do a decent job for a cheap price.