After a number of posts regarding cheaper options I thought I would quickly list the possibilities. While it is true that specialist plant grow bulbs will more than likely yield better results, you can buy these and save some cash. They are available from any lighting retailer.
Philips aquarelle (only T8 imported to SA)
Osram fluora (only T8 imported to SA)
Sylvania 865 "daylight"
General Electric 9325
Combinations are good. Try and combine a daylight tube with a pink plant tube such as the fluora or the growlux.
For those more technically minded, here are some links to some nice articles:
Use a translator for this link http://amania.110mb.com/Chapters/Tech/light-par.html