i have Home 500 plan.... there are 3 options for modems. 1) rent it from BSNL 2) purchase from bsnl (costs around 1000/- INR) 3). purchase from anywhre else (entirely ur choice)
ur monthly bill will be around 500+60=560 INR including taxes...
Ya, if u pay in advance for 1 yr like me then it wud settle in rs 5000 total... (u'll save 1000 bucks)
no installation charges (atleast they didnt take anything from me when they installed at my home except for TEA

)
the modem they give u (if u purchase from bsnl) will be ZTE ZXDSL 831AII (as of now they are giving this model.. this cn change in ur area)... cost- 1000 INR
i wud not suggest renting a modem from bsnl because they will give u second hand crappy model...
Call charges are not affected by internet... u can use the fone and internet simultaneously (thnks to gud quality of splitter they provide)
if u dont have a bsnl landline then u have to CHECK the option of requiring a bsnl line while filling the form...
Hope i helped u... enjoy ur broadband journey