Bought one today for $3,561.65 (used my $50 signup code) using NAB EPP, not sure if it's available in other employee portal.
Samsung QN800B 75" $3,611.65 was $6,499 (~44% off)
Samsung QN90B 75" $3,874.22 was $4,999 (~22% off)
other model prices in the link below
Update!
QN800B 75" now $4874.25
QN90B 75" still available for $3874.22
Doesn't look like it actually retails at $6499 anymore.