Atul - I understand you like to have a company of a dog, my comments were not based on anything but to make you take a concious decision. I have a KCI registered lab. but I did not thought of show or anything when I got her, it was just a passion and had payed a good amount because I wanted the pet to have true characteristics.
Think of this, you get a GSD and when it grows old you see him very voilent and other things which is not true for GSD.
Since you are a student and does not have enough earning, think 100 times before you go for any of these gaurd breeds, as Sindhoor mentioned there is expense around Food, Medicine, toys etc. these breed good amount food and vitamins etc.
Hence I suggest - wait till the time you earn enough to take care of a pet and take responsibilites - if you still insist, I would suggest to adopt a puppy - which would be free to cost, there are pupps/ dogs available at animal shelters and there are few in Delhi area.
Check this site you and you might want to give it a try.