Was already on promo at $1749 compared with Sony and other retailers $1795, but today there was an additional $80 off on offer bringing it down to $1679.99.
They had a good amount of stock on the floor in boxes, says the offer ends today but given they are open until late still gives you good time to go grab one.
You might be able to try your luck getting Sony to price match but not sure if they allow Costco.
have linked also to the sony website
https://store.sony.com.au/television-4K-X9000/XR55X90J.html
From the photo it seems today will be the last day for this in store promotion.