My first grow was with 3x42w CFLs on 3 small plants. I got about 8 grams. I feel I could probably get double that amount now with the same lights, but it's still a very small amount of light.
Finding the right LED is really easy now, actually. Just hit up EBay, search "led grow light" and change the 'Sort By' option to 'Price: Highest first.' You can grab a 90w UFO for around $130-150, $~200 for 120w, and ~230 for 150w, and about $300+ for a 250w light. For only a couple plants, I wouldn't recommend anything bigger for just 2 plants.
The bag portion doesnt need light, the idea is to give the roots extra heat, but heat rises and the plant needs the light for food and growth. So it helps itself so to speak. You can create a similar design with 5 gal buckets and 2 1/2 gal too. You can acually plant herbs on the top too!