the cheapest you can get would be going the Lights of America, power compact street light. these are 65w and are 6.5K in spectrum they are about $30 a pop. 1 would work, but 2 would be better if you want full coverage and good intensity. you will be able to keep just about anthing you want under them.
now for the down sides. they are hot, they will need adequate ventilation or your tank will overheat. fans or a tall canopy are a must. another problem would be that they are quite yellow in spectrum for our eyes the corals would like it but you may not. about your only option would be to add
actinic lighting somehow. this would bump up the price. you would prolly want an
actinic bulb for every LOA you use.
this is one heck of a deal for supplimental lighting.
lighting is the most expensive part of doing a reef tank. since you are just starting out i would go with one LOA light and one of the above PC lights for actinic supplimentation. that would put at one heck of light fixture for about $100.
G~
