Dee's Gym System

I have a business of supplying gym/sports products, to various fitness clubs in my city. Some products are produced in the factory, while some are assembled.I need a system that would keep a track of the raw material that I buy from various suppliers. Depending on their product that they supply to me I need to maintain level of the quality supplied. System should also maintain the products that I sell. The selling might also include some discount that I give to the suppliers.I provide some discount also if the delivery is late. Count of the products reduced from the inventory should also be maintained.