someone is selling an iPhone 6s 16gb for $300. And he is giving me 1 year international warranty on it . do you think it is an original iPhone or a fake copy?
I don't know, and there is no way for any of us to tell without actually having the phone with us. If you're buying the phone in person, inspect both the hardware and software BEFORE giving the seller any money. If you like the device and find that it is a real iPhone then buy it, if you don't or are suspicious, then pass on it.