My brother always used to buy with coupons, he knew every new site which offers discount coupon on purchases for first time user or repeat users, and he is used to create accounts on these coupon sites and used these coupons for buying stuff from online e commerce website like amazon and flipkart.
He saves lot of money doing it, almost every purchase he makes he uses some kind of discount coupon from some website.
Actually its lot of work, I cannot waste my time around 1-2 hours just to save my 100 rupees, it requires research you scan through these 1000s of coupon website, read their coupons terms and conditions , on how and where you can use them
But it also saves your money; I used my brother shopping skills to do online shopping and saved my money without wasting any of my time.
Everyone have these type of friends who knows where to buy best and cheap, who seem to always have coupons for everything, use their skills and save your money.
Some of the guys are expert in product research, they do extensive research before buying any product, for example if they want to buy mobile phone, they will search for the best mobile available in their budget, you can use their product research skills in making better buying decisions for yourself.
Checking for discounts is hard work, if you know someone who has mastered these skills, use their skills save your time and also money.