2001 Saturn SC1 intermittant non starting

My car usually starts but when I really need it it doesn't. There's no ryhme or reason. I can turn it off and it may not restart. It may not start but then will later. It has nothing to do with how long since I last drove or the outdoor temperature. All dash etc starts so it is not dead. I have replaced the clutch interrupter switch but it is still having the same problem. I can pull key out and car can still run. Sometimes it's hard to turn the key as well. I am doubting it's the starter and don't want surprise no starts and can't afford to replace things until a mechanic gets it right. They can only diagnose it when it doesn't start. But it always starts when I take it.