"A lot". I know that's not a fair answer but everyone will be chasing AP and that's what drives the price "demand" side of the equation. Pop on Craigslist for an example. Price out iPhones and compare the 6+ and 6 to the 5S/5c. These can all still be pruchased new from Apple too. They are fractional valuations versus their new retail costs. Everyone is chasing the 6 series models so they are offered up at prices very near the retail (new $650, used $550). The 5s and 5c can be had for @ $200 but they are $450 new. A model that isn't sold any longer like a 4 can be had for $100. The difference is both excess supply and underwhelming demand for the older models even though the differences aren't truly that large (with the AP being the one that arguably is revolutionary). If I had to put a value on AP, I'd say $6500-$8500 will be the Delta tween like kind vehicles with and without AP. That'd mean you can buy a fully loaded CPO P85 without AP or a CPO base S60 with AP in my opinion.