When I bake vegetables in my wok, I see small black specks appear on the vegetables. Does this mean that the fire is too high, or that my wok is not well enough prepared? How do I find out?
Non stick is a bad choice for a stove top wok as the temperatures produced can exceed the acceptable temperature range of the coating; if you have one of the electric plug in woks, they don't get hot enough to do a good job. In either case, get a steel wok, you can see if it's clean, and sand it or steel wool it or use abrasives on it if it gets messed up and you can get it red hot without damage.
Really really cheap ones work just as good as the expensive ones, just make sure they come with a burner ring.