You can get a Current satellite 20" 40w PC fixture with a moonlight for about $50 new, but it comes with a 50/50 bulb and you need to replace it with a 6500k bulb, so that adds cost.
Heck, I have one I could have sold you cheap when I was back there, not going to use it now that I have a 150w Viper MH for my 30 cube
I could probably ship it to you fairly cheap, it has a new Sunpaq Dual Daylight 6500k / 10,000k bulb in it with about 2.5 months use.