why the price of same type of nokia is more diffent in diffent shops?

Tweet

tonight I buy a new type of Nokia mobile phone in one shop. Before I make a purchase, I compared the price of the same type of nokia in diffent shops. The result make me feel suiprising, the price is highly different. The highest one is even the double to the lowest one. I thought the quality may be different, the price more high, the quality more well. But I am wrong, the product is wholly same. Then, I am lost, why are the price so different for same Nokia mobile phone?