Alright, so I'm not actually #SunDIY ing anything right now, but I thought I'd share this tip for folks who wanna get into #hydroponics cheap.
There's all kinds of growing medium - Perlite, expanded clay pellets, rock wool, and coco coire are probably the most popular. Pretty much any inert substance you can think of can be used to grow stuff in a hydroponic system. There are advantages and disadvantages to all of them, but almost none of them are both Cheap and Available at the grocery store.
I got this pool noodle for $0.95
One of the advantages of this method is that you don't have to buy any net cups.