As the title suggests I have a Linksys WRT1900AC in my router collection - has been used for around 2 months on OpenWRT and has been excellent for unblocking all the sites via my Unblocker tutorial here.
It'll arrive to you in perfect condition, hopefully bubble-wrapped in some sort of box - what I am trying to say is my partner cleared out my box collection so I no-longer have the box for this. It'll also come with the stock firmware running on it flashed via Serial / TFTP to ensure my configuration was 100% wiped.
I am thinking $200 for it, you can buy one brand-new for around $300 so seems fair. Runs OpenWRT very well and has excellent WiFi and speeds. I was using it on a Snap 200/200 UFB connection and it didn't break a sweat.
Am selling as I seem to have a router collection and have decided to use my R7000 for now :)