There are many online retailers in India, the most famous ones being Flipkart, Amazon and Snapdeal. Popularly, they are known as e-retailers. I would checkout the latest mobile phone models from these sites and select the one that meets my expectation in terms of price and features. Thereafter, I'd select my mode of payment, either by Credit/ Debit Card or Cash Against Delivery. Finally, I would go ahead and place the order.
It may be noted that these leading e-retailers extend a free return option for customers in case they do not like their products on receipt. However, I'd only exercise this option within the stipulated period if my mother does not like the article, there is some damage in transit or there's some functional defect.