why would a product have more than one price if it only has one supplier?
coz my company wants to know the stock of certain Product with the price of it..so it can sell to the Customer but with Different Price..

Are you going to use it in a report where you will show the variation in prices from a period of time?
not exactly like that..but i want to make a report that show which Products that sold to Customers with the buying Price and the selling Price..so we can calculate the benefit from the different Price..and maybe how much stock left for certain Product, what Price..etc

is this clarify ur question?
NB : maybe my field name is not make clear the purpose of it..