The Black color was previously $398 then around mid April was raised back up to $528. Now back down to $398 again, BUT…this time the Dusk White edition is also going for $398.
If you want the black, you can get them from these stores:
JB Hi-Fi ($399) : https://www.jbhifi.com.au/products/gopro-hero7-black-4k-hype…
Harvey Norman ($398) : https://www.harveynorman.com.au/gopro-hero7-black-4k-hypersm…
Good colour. Not so good price ~