The problem with having small CFL grows is as the plant gets bigger it needs more light so you have to keep adding more bulbs, unless you buy real 100w+ cfls.
Thats why I invested in a HPS, got it for $60 off ebay 400w with a MH growlush retrofit unused and a HPS globe which I replaced (use the oldie as a spare).
I know you are on a budget but just check for those bargains, if you make enough weed you can sell a little to cover your costs.