You can go with a 42WCFL (2700K 3200L) for ~ $7 CDN, and pair it with a 42WCFL (6500K 1620L) ~$6 to start. It's plenty enought lumens for right now, but you could double or tripple it for huge amounts, and do it cheaply too.
I used the first pair on a little plant I found, and it's coming...