I feel your pain. I just finished my store and have been working on it since March of this year! I know next to nothing about PHP or Mysql, but after successfully installing 40 contributions and getting everything to work, I'm learning
You have to remember that it's free and like many free things you get what you pay for. I have tried Zen Cart, Cube Cart and another one, but went back to Osc. The others were harder for me to work with and don't have half the contributions that Osc has. The support community is pretty good too.
Good luck with whatever you try. If you need anymore help, just shout. I will do what I can (which probably isn't much)