I have a friend who wants to sell his Canon 70-200mm f/2.8 IS for $700, which I know is a steal, but I am wondering how much it will cost to have it fixed. The problem is with the zoom- as it won't zoom in or out. Everything else with the lens is fine... nothing wrong with the focus or anything else. Does anyone have any idea of an estimate for having this problem fixed? Is this even worth the "great price"?