Is it safe by buying from an online dealer?

I contacted a online dealer and he said he wuld sell me a new sealed iphone 4s 8gb at 15000 rupees only! So is it safe buying from him is there any fraud in it?

By seeing your deal the chances of fraud is more as iPhone 4 8GB is selling now officially at 26.500. And he is selling u a iPhone 4S [ which is far better than iPhone 4 in specs ] at only 15 K, well this price could be good if it would be a second hand deal but you mention sealed.
So, i will not recommend you to continue. I'm not saying that all online dealers are fraud but this 1 looks like it is as the price is very low as 4S is officially selling around 37, 000

Those are going to be counterfeit Chinese phones not real iPhones. Contact the Apple office directly - they have a list of every authorised dealer and I can guarantee they will not have a record of this dealer. If he's not an authorised dealer then there's no way he can get real Apple products to sell in the first place