Tata Docomo gives 100 MB free data with 5 days Validity.
To get it:
Go to this page – http://www.tatadocomo.com/reload.aspx
Enter your 10-digit prepaid number.
Click ‘Reload Now’
You will receive a confirmation message from Tata Docomo that your phone is loaded with 100 MB.
Please check the Terms and Conditions before loading.
Note: You might have to restart your mobile to utilise the free data.
Try this and let me know how it worked.