@sathish
what i suggest is u go for a 250/- per month plan which will give u 400mb of surfing at day time .. and in the nights (2-8am) use ur frnds account. this is the best option for u . regarding the modem buying frm outside , u will definitely get a btter modem such as dlink but then the cost will be high , the bsnl modem is quite decent for 1200/- bucks.