Basically it boils down to this, the higher the wattage you can get out of a single bulb the better. The higher it is the better the penetration will be, so you want to shoot for the highest bulbs you can afford instead of spreading the money out amongst a bunch of smaller wattage bulbs.
CFL's: Available from local stores you'll have ranges of 60-150watt equivalent bulbs, so those range from 13-28 actual watts. Given the statement earlier, having two 13watt bulbs is not even close to the same as a single 28 watt bulb. The amount of light in lumens is going to be approximately the same, but because its given off by two separate light sources the amount projected is significantly reduced.
HPS: Available online and some local specialty shops you'll have ranges of 70-1000watts, the same applies to HPS in regards to penetration. Two 70watt HPS bulbs are not remotely the same as a 150watt in penetration factor.
The lower the wattage the lower the heat, the closer you have to keep it to your plants to keep them from stretching.
Now comes the "Where are you going to grow?" Question...when using low wattage lighting systems you want to get the most out of it possible. To accomplish this you must keep them close, and keep the light contained. 4 CFL's hanging from a ceiling over a couple plants in an open area will do jack shit except make the plant very thin and climb as high as it can. Now take those same for 4 CFL's and enclose them in a 1'x1'x2' box with reflective material on the walls/floor and a reflector just above the lights will be a completely different growing experience. When you concentrate the light into the area that's what you need for good growing and penetration. A good way to look at things is if the box you are growing in with the lights going is overheating it at like 100+F and requires you to put in ventilation to keep the temps below 85F, it's probably going to do OK, not great, but OK.
Since you are going to be using autoflowers, depending on the strain, they shouldn't grow more than 18-24" in height. There are some strains that are coined as "autoflower" that are actually iranian crosses that are "early flower" that will still flower under 18/6, but take a little bit longer, but dropping them to 12/12 after a month they will bloom quickly and finish in the advertized timeframe. Since you are not an expert(nor am I), expect to go 1-2 weeks beyond what the seed seller says it will take to harvest, do not harvest early
I didn't even touch the neuts/grow medium part, depends on what you are doing, if using soil make sure its airy and not dense, good way to tell is when you grab a handful of it it should feel a bit squishy and if you compress it with your hand it will hold its shape, but if you touch it with your other hand after compressing it it should start to fall apart.
So, in a nutshell, buy the highest powered light(s) that you can afford, grow in a small enough space for those lights, ventilate it, follow the growing guidelines for the strain, be gentle in watering/neuting, dont give low strength neutrients for the first two weeks, and gently increase it, etc...
Hope that all helps, sorry for the long post, just don't want you making the same mistakes I have made in the past