how to offer your site user free coupons
I see many websites offering many kind of coupons like food or clothing. I wonder How do they offer these coupons. Do they have any contract with other companies or something similar. Here is one site for example offer coupons with online phone recharge Free Online Prepaid Mobile Recharge India Vodafone,Idea,Airtel,Reliance,BSNL,Docomo,Tata Sky,Dish TV & Videocon D2H
Does anyone have any idea?