At some point you'll need a HPS light for budding. You can get them online for $100-$500 depending on the watts, ballast, etc. For what you're describing, you'd probably want at least a 600-watt light. Also, if your light is too orange, your plants will get too tall, which would be a problem in a 4-foot-high grow area. A bluer light like GE Daylight, which has a spectrum of 6500K, would promote shorter, bushier plants.