Compose a Text Message on your Phone, Type RD 50MB and send it to 797 ( Type it exactly as it is)
You will Receive a Message from Airtel that your Account has been Credited with 50MB.
Check your Data Bundle Balance by Dialing *141*712*0# and you will see you have 5GB or 5123MB on your Phone.The Bundle is to Expire by March, But if you dont want it to Expire, A day before the Bundle is to Expire, Load a N1000 and Subscribe for the Airtel 100MB, All your GB will be Extended and you can continue using it on Both Phone and Laptop.
You can Perform the Step 1 Above over and over again to Get More GB for Free