Answer:
when to buy.
Explanation:
On an average there is no major difference in the price offered by various vendors, still, there are market fluctuations in the prices of goods.
Accordingly, customer shall verify his needs towards the product not only about from where to buy but also when to buy.
As with time there are price fluctuations, sometimes modifications in goods too are also made, therefore, a consumer shall know from where and when to buy the goods, depending on individual needs.