The 18 TB drives are no longer available.
Apparently, things worked out for Best Buy.
They refused to sell the drives, at the sale price. Then when they made their drives available for sale, they sold out at the higher price.
Best Buy knew that Black Friday was coming. They knew that they did not have enough stock, and they still advertised them for $299.99.
I grabbed the 18 TB Western Digital Elements drives from B&H when they advertised them for $299.99 and they actually sold them, as advertised.
B&H has now raised their price to $379.99 and have none in stock.