man you can totally build it yourself. Look into Deep Water Culture (DWC) for a simple yet effective hydro set up. However, this may not be the best if your are growing from seed, as when you try to take out your males your roots will be quite tangled. I'm doing a drip system, and i bought the water pump, hoses, and drip stakes at a hydro store. I got my resevoir and root chamber at walmart (plastic tubs). You can find little water pumps probably at walmart or home depot. Drippers you might can get at a garden store (not sure). You can always order stuff online.

But you don't need to buy a kit.

Also, make sure your CFLs have a good light spectrum for you plants (~6500k for veg and ~2500k for flowering), or just get both to give a more balanced spectrum throughout the grow. I do recommend getting some good nutrients. A 3-part nutrient system works the best (General Hydroponics and Advanced Nutrients make good 3-parts).