T24 sims are provided by Big Bazaar and you get free talk time when you shop at any of the Future Group stores like Big bazaar, Pantaloons, etc.
If you shop at any of the Future group stores, you can get talk time loaded from Rs. 10 to Rs.150 based on your bill amount. For regular shoppers this could mean freedom from mobile bills.
T24 is backed by Tata Docomo and it does not have good coverage in my area. Besides that, the talk time does not get credited sometimes and you will have to speak to customer service agents who insist on talking to you in Hindi even when you have selected English option.
Overall an average experience, but then you get what you paid for - nothing in this case