Rs 98 / month is for 2 GB of EDGE data per month. That is the normal charge in India for every mobile customer. This is not a special tariff for this tablet.
Seconded. I currently live in Bangalore and pay just Rs 400 (about $8) per month for blackberry services + unlimited 3G usage. I had this Rs 98 plan a few years ago when I was in college and didn't have a 3G capable phone.