Varying purchase prices for a single inventory item is where things get tricky. I would need a way to record each purchase price and ledger's reporting facilities would also need to be aware of what method of inventory valuation I am using (LIFO, FIFO, weighted average, etc.).
A manufacturing operation would add further complexity in inventory tracking. Both finished products and raw materials need to be tracked and there would need to be some way of showing the relationships between the two. For example, 1 loaf of bread is equal to 0.5 lbs of flour + 1 tablespoon of yeast etc.
