Coupon required to get this price (see below).
Sony NZ have price matched PB Tech and are selling these headphones for $375, with free shipping on all orders over $200.
However on the Sony store if you register for a new MySony account (with an email address not before used), you get emailed a unique 10% off voucher code. Be sure to tick the second check box when signing up, in order to receive the code. Mine did take 15 mins or so to come through.
I was able to use my code and place an order with a total of $337.50. [Update 24/11/23 - Price now slightly lower at $335.70 with coupon]. This is the best price I've seen in some time for these eternally popular Bluetooth noise cancelling headphones.
There may be some other bargains out there of items that they've price matched that you can then add the voucher to. Buried within the T&C's are a list of excluded items the voucher cannot be used on (All PlayStation products, Camera lenses and a few others).
Might be good on WH-1000XM5, WF-1000XM5, and Bravia TVs perhaps? They do also have a price match request feature that may or may not work with the welcome code.
I am unsure when this deal will end but PB Tech's cyber Monday supposedly ends at midnight tonight.
I still use my xm4 daily (had 2 of them black and blue). Fantastic headphones and ANC. Have not even looked into xm5 replacements this year.