If you are a Uninor (India) user, you can activate special tariff voucher (STV) by simply dialing the USSD code.
To subscribe to a voucher, the customer will need to dial the USSD code in format *222*7*xx#.
Like if you want to recharge SMS pack of RS. 27 dial following number:
from your uninor number.
The amount equal to the voucher MRP would be deducted from the customer’s main balance and the voucher would be activated immediately. If the customer do not have sufficient main balance, voucher activation will fail.
You can check latest STV plans on uninor website.