Let's see, this is a low speed 2x16GB DDR4 kit for $300.

The closest option on the pcpartpicker chart was about $75 as a stable price. So that one's only a 4x increase.

Versus DDR5 where... it looks like a 5x increase to me? I'm seeing a jump from 200USD up to 1000USD. Edit: Oh there's an extra jump in the last month on the CAD version but not the USD version.