How much will an iPhone 5S upgrade be?

I've had my 4S for two years and AT&T told me I have an upgrade available. I want the gold 5S 16 GB but I'm not sure how much it will cost. $150? $199? I haven't gotten around to calling them yet about it.

Get around to calling AT&T for the most accurate answer.

$199 plus the 30-45 dollar upgrade fee. Unless of course they are running a special where they take a bit off the price.