Be sure to add proper ventilation to your box. If you're trying to go cheap, I suggest computers fans for intake, or a passive intake, depending on the size of your box. If you're talking about using 5 gallon buckets, I'd go active intake. Use a bathroom fan, or two for your exhaust. You can pick one up at any hardware store for around $30-$40. What kind of soil are you using? I'd suggest spending a little on nutes. I'm using Age Old Organics Grow and Bloom, plus Fox Farm's Happy Frog Flowering. If you can only buy a Grow and Bloom, I'd suggest Age Old's. They have most, if not all the micronutrients you need: boron, zinc, manganese and a few more I can't name off the top of my head. You can get a bottle for $15 and it should last you a long time. You'll also need a Calcium/Magnesium supplement.