Hey, I recommend going HID (which includes HPS and MH) if you have the space and ventilation for it. I started with a 250W MH/HPS for my first grow and I'm never going to try CFLs except for supplementary lighting.

250 Watt High Pressure Sodium Light Bulb
250 Watt HPS HID Light Bulbs Light Bulb
-those are the cheapest HPS/ballast combo that I've found. It does not include a light fixture (the thing that the bulb screws into) but you can find one... search for a ceramic mogul base

Also, since its so cheap you'll also have to wire it yourself so here ya go...
How to wire your own Marijuana Grow lights &Save Money & Wiring 2 Rooms With 1 Ballast,
Just use some wire nuts from home depot and its really easy

When you want to upgrade, get a digital ballast. I've got one and its so much more efficient and runs cooler.