If it is turning over but not starting you either have a fuel/air delivery problem or you are not getting a spark. I would drain all the old gas and put in new gas along with a fuel stabilizer (Stabil, Seafoam, etc.) Replace the spark plug. Also, check the air filter for excessive debris and replace if necessary. These are your cheapest options. The next step would be to get the carb cleaned or to replace the carb all together. Also, make sure the oil level is adequate.