ramesh ji i am also a TA and my income is like slightly above yours. it depends on how u manage ur money. for me , with all the rents, grocery, fone bill, calbe, internet, and my pocket money, i can still manage to save aroud 300-400 dollars per month. so the main thing, if u want to save moeny, is dont expense on unnecessary things coz in the US there are a lot of things that can make u expense ur money. so it depends on how u handle ur money. regardind ur question about Green Card, Mr, Pire has answered very nicely an I appreciate for his generous suggestions. Follow what he has suggested. have a great journey and good luck for ur work coz TA is a very challenging job.