The answer to your latest question is a matter of how big you want to go and how much money you are willing to spend. If you are interested in getting 2-3 plants to harvest and will be happy ge3tting an ounce out of it, then you can do that fairly cheap. You can get the 300w cfl lights in 2700k spectrum and rig up a holder so that you can put 4 of those in a small space and then also get 4 6500k bulbs to run for the vegging of the plants. This will work and will produce some bud, but as THG said, the results for overall cost and sweat that you put into it will be somewhat disappointing.
For about the same initial cost you can order a nice 250w HID with a digital ballast and 2 bulbs(1 MH, 1HPS) and the reflector to go with it. ($135.00 shipped to your door inside of a week from YESCOMUSA on EBAY) I have ordered several kits from them with complete satisfaction. This unit will cover an area that is 2ft x 3ft, like a small closet. You would not be able to grow them very big but they would yeild considerably better.
However there is more to growing MJ than just popping some seeds in dirt from the back yard, sticking them in some light and watering them occasionally. Growing MJ is different from growing any other plant, period. While there are some similarities, MJ is very particular to its needs, and some strains are very very particular and down rite difficult to grow unless in perfect conditions.
That said, you will need to enclose your space with reflective walls so that you maintain the most of the light energy that MJ needs. Within the right sized closet space is fine. Just make sure the walls are clean and painted flat, brilliant white, or get some reflective insulation material from the building supply. I use and like "Reflectix", it is a mylar covered bubblewrap sheet that comes in rolls and is rather inexpensive.
The next thing that is of utmost importance is your soil. DO NOT GET Miracle Grow prenuted soil or ferts as this is toooo strong and will kill the babies. The best option is to get the good soil from online hydrostores or if you have a nice hydro store nearby. you will need some quality soil or medium to grow them in and some quality nutrients. You don't have to spend a boatload to get what you need for just a few plants but you have to be willing to spend some to get decent stuff or else you are relying on luck to give you a weak to mediocre harvest at best. Good luck friend and read everything you can (especially here).