The growlight I made from scratch in my basement, is situated between my overhead rafters. The gap between the rafters is just over 14" wide, and the light is 48 inches long. Inside the grow light are 16 - 23w CFL bulbs I bought "on the cheap".
I live in the Raleigh/Durham area, and Duke Energy is the electricity provider. Duke has a special program to encourage customers to get off the incandescent bandwagon, so they subsidize businesses that participate in their program. I first learned about this, when I was out going through thrift stores, looking for great deals. Must be the barbarian hunter/gatherer in me.
The Habitat for Humanities thrift store had a huge pile of CFLs stacked up, in packets of two bulbs. The price for a two bulb pack was $1, and you could choose between 60/75/100W, all for the ridiculous price of "two for a dollar". The only catch was that all the bulbs were Warm White. No daylight White.
Well, I bought a bunch of them, and actually called up Duke to see where else they had their program. I told the lady at the other end that I didn't care for Warm White(I don't), and preferred the Daylight White more. So she gave me some more businesses in my area, and WalMart had a couple of stores in the Cary Area. Not all WalMarts are in the program, but the one I went to, was selling both Warm, and Daylight White CFLs in four bulb containers. And while not quite as good as the $.50/each price at the thrift store, a box of four was $3.48. Still a great deal for 23W bulbs. So I cleaned them out of Daylight bulbs(8 - 4 bulb boxes). I was in hog heaven. I have since discovered another WalMart in Raleigh that has the same program, and I bought another 4 boxes, so I'm stocked full of CFLs for all sorts of uses.
If you will check with your energy provider, you may find that they too offer incentives for going to CFLs and perhaps the same deal as I have here in the Raleigh area. You can't beat those prices.
And with so many cheap CFLs, I am thinking of all sorts of little projects to experiment with. I'm even thinking of mixing in CFLs with 15w LEDs within the same fixture, since I now have 20 of the Chinese 15w LED light fixtures. All of them are the screw in type, so I don't need to worry about all the calculating and power supplies. I just hook them up in parallel and I'm ready to go. I'll take some pictures and post them here later after Christmas.
Oh, one other thing. $3 for that aluminum baking pan is way too much. If you go to a Dollar Tree, you can find a wide range of these bakers for just $1. I actually bought a couple earlier, but quickly realized other possibilities with bigger fixtures. The most expensive parts I pay for are the bulb sockets and the "Y" splitters. In fact, I'll probably resort to buying them on eBay from a Chinese dealer, where they are also cheap.
Everything else is less than a buck. Oh, wait a minute, that's not entirely true. A 6ft cord and plug was $1.39 at WalMart, and I bought 4 fans on Amazon for a little over $5 each. Other than that, everything else was as cheap as you can get. The CFLs were $.50/each for Warm White, and $.87/each for the Daylight White. You would be hard pressed to beat that one, don't you think?