BUT... from what I've read on all of these forums, it's a very scientific and complicated process. How bad will my plants turn out if all I use is some good soil, some grow lights & good ol' fashioned water?
Not very well because you need fertilizers of some sort.... can't use MG with nutes. Seriously though it is not that hard. I have been growing hydro for years and even it is easy once you get setup. Read A LOT and you will save yourself a lot of money and time.
I work full-time, have a house, dogs, cats and a significant other and am VERY lazy so I check my plants every 3-4 days and adjust the ppm of the nute solution with a $20 meter. Every week and a half I change the water out and re-add nutrients. Raise the lights and adjust as needed. I did this with $200 worth of lights and fans, $50 worth of pvc and $50 worth of hydro supplies: