Sometimes, I’m still amazed that you can get a 55" TV for $398, let alone one with 4K resolution, HDR10 support, built-in Roku software, and the ability to use your phone as a remote. This has gotten down to this price a few times in the past, but it usually sells out quickly and goes back to $450.
It’s 1-3 weeks backordered, but Amazon tends to under-promise in that department, at least in my experience.