hmmmm, when adding corals you generally wanna go for about 5w per gallon, so that around 350-400w for that tank.
you could get a arcania classic metal halide single 150w which is about $180, if you put corals under that they will do fine if its the general hardy corals like zoas, leathers, mushrooms, colts that kinda stuff.
if you set that up in the middle you could then get 2 really cheap PC lights and put them either side. would look ugly from the outside but considering they will be hidden it'll light up the sides.
if not with the corals the lighting will probs be quite expensive.