For $100.00 more you can buy a new 65" at Sams Club.
$579 refurbished at Walmart: https://www.walmart.com/ip/Refurbished-Samsung-55-Class-4K-2160P-Curved-Smart-LED-TV-UN55MU850DFXZA/690563869
This tv was on prime day new (not refurbished) for $600 last year. Also I own one and its garbage. The smart functions constantly fail because the wifi software is bad.