I needed to buy a significant amount of 2TB(+) 2.5" drives (for a personal server project) and managed to (just about) get them under £15 a TB.
Note to self, next time get a server that accepts 3.5" drives: https://diskprices.com/?locale=uk&condition=new,used&capacit...
Edit: there's a new entry in the sidebar.
Still need to add more filters, of course, but figured I’d throw it out there as well while it’s in progress and topical for the discussion.
[0] https://gpupricecompare.com