Its really wise not to get flown in impulse of buying things which one doesn't need/afford.
Ultimately we are here to earn and save money for the things we are liable to.
But still, if you wish, ask for somebody's credit card, buy the phone choosing the installment option.
Or, borrow money from someone giving him 3 cheques (Which I am sure u don't have).
I hope ur query's been sorted...