It's really expensive but they throw the rest of a new machine in with it as consolation.

EDIT: Sibling beat me by a couple minutes. DO great minds really think alike?

Sure it is. It just comes with a new Mac.

https://www.apple.com/us/search/memory lists 10 products (for the 2018 Mac Mini, 2019 Mac Pro, and 2019/2020 5k iMac)

I'm not sure their memory pricing is competitive these days anyways.

You can still buy RAM to go in 68k Macs, just not from Apple dealers.