Yeah...   those deals... ug... 
I have a Nexus 6 that I got shortly after launch.  And me, like most everyone else who bought one back in the day, are kind of left out in the cold.  

  If you can pick up a NEW one for less than $300, that pretty much destroyed the used market.  Nearly everyone who had one would end up selling it for a big loss.  Hell, I have a small crack in the corner of my glass panel (closed quarter circle crack across the top corner, so its cosmetic).  A new panel is around $200 and I am guessing that if I were to try to sell this one, I wouldn't even be able to recoup the cost of the screen replacement.
And I am really eyeing the 6P, of course, the thing seems awesome.  But I am having a REALLY hard time justifying the purchase to myself because the 6 runs so damn well.  It's fast, smooth, gets great battery life.  And I disagree with those 'cons' everyone mentions.  I've had no problems with the camera and the quality of pictures it takes.  Other than the low screen brightness (which I can tweak with a widget), the screen has not done me wrong.  Oh, and I got giant mits, so the size is nothing other than a BIG plus for me.  Even on a G3, it was a little cramped when I typed.
So I can think of no reason to get rid of my Nexus 6.  Well, other than 'because new'... which is a powerful force in and of itself.  But for the prices that people can get a Nexus 6 for now, it's a crazy value.  I've said it plenty of times before, but the Nexus 6 completely wipes the floor with any phone that is available for the same price you can get it at now.