The best way to do it, as a former Apple Store Employee, is to use the carrier promo in store or online. If you do the promo through Verizon, the entire trade in value of 800 gets split up over bill credits. With Apple, you get $450 instant and only $350 is split over bill credits. This means you still get Apple's trade in value and the trade is done through apple (in store or mail in), and you also get the bill credits coming. If you leave Verizon early, you still got Apple's trade in at the least.