Firstly Bsnl Rs.249 broadband + landline combo offer has been extended to 31st March 2017.
Bsnl Rs.249 plan offer come with zero installation charges however many times they put installation charges in your first bill. You will have to visit local Bsnl exchange office to get reversed if it happens.
You will have to deposit total Rs. 750 while booking the connection(Rs. 500 (refundable while closing connection) security + Rs. 249 one month advance rental which will be adjusted in last bill or refunded).
If you buy a optional landline instrument then you will have to pay Rs. 500 approx.
Also on opt to purchase wifi modem cum router for Rs. 1500+tax.
Else you can also choose to rent it from bsnl at Rs. 100 + taxes per month which will added in bill each month.
I would recommend Tp-Link adsl+wifi router from flikart or amazon. Comes out cheaper with 3-year warranty.