Very rarely, Post-Paid Subscribers are Pampered by the Telecom companies. BSNL 3G has extended an offer for all 3G Post-Paid Subscribers by offering 50% Free Data Transfer on all 3G data Plans the subscriber is currently subscribed to with a small condition that your current plan must be of at least 1GB Data or More.

So if you are in BSNL 3G Plan 369 - You are eligible for 1 GB data Transfer. Along with this offer, you will get 1.5GB.
For BSNL 3G Plan 649 - You are eligible for 2 GB data Transfer. Along with this offer, you will get 3GB.

This is valid only until March-31-2012.