You can get great sounding 6's for a lot less, people with lots of disposable money push things up ridiculously, simply try some from Brent Jesse
https://www.audiotubes.com/6sn7.htm
He's got a lot of Baldwin Organ Factory stock, $30. each, they could match some for you.
I had 6sl7 and 6sn7, Cayin OEM, (made by ____?), loved them. Blew one, had a used GE sounded like the Cayin, use it temp and get matched ones, right?
Tried some new Sylvania's, matched pair $160., hated em, Brent Jesse had me 1st break them in (simply leave on for 60 hrs, no signal needed), then let me return for full credit, and tried some General Electric (based on my used GE sounding so good), matched pair only $80. They sound great, as good as the Cayin Branded whatever they are.