Freecharge is giving Rs. 50 Credit on the minimum recharge of Rs. 10. All you must have is a freecharge account and use promo code from this page. If you don't have free charge account then you must a valid email id for sign-up.
Follow the procedure if you have android phone and get free talkvalue of Rs. 50.
How to recharge-:-
1. Download FreeCharge App.
2. Create a new FREECHARGE ACCOUNT Then Enter your mobile number, operator, amount = 10 (Min amount is Rs. 10) and CLICK ON Recharge mobile