Who I have the same questioned this topic

So I have an iphone 6s, but it is water damaged. (It doesn't turn on) I am due of an upgrade in less than a few months, so I was wondering If could pay off the rest of the money that I own for that phone. And then use that device for trade in value to get the new iphone X? Or could I just get an new Iphone X, but woundn't get the trade-in value because the iphone is broken.