If you are going into a retailing business - buying products from a wholesaler and selling it by retail - what you should have done is to survey for the prices of the goods that you intend to sell. If you bought that product for Rs. 50 and the stores are selling that for Rs. 50 then you cannot earn a profit anymore. If the stores are selling that for Rs. 70 then you can sell that for Rs. 65 and still earn a profit of Rs. 15. But you can only do that if you know the selling price of the stores.