What kind of program do you need?
If you need one for scripting, use Notepad. It's free, simple and even a fool can use it.
If you need one for modeling, get Milkshape. It costs, but try out the trial first.
I used notepad for scripting and stuff since I was 9, and I had no problem using it. Milkshape is also very simple when you get used to it.