I hold a lot of physical gold, arms, ammo, emergency rations, antibiotics and other medical supplies, solar power components, a seed bank in a Pelican box, a lot of diesel, tons of fishing equipment (I'm on the water), and perhaps most importantly I make sure I have the knowledge to survive (which may be the most precious commodity). All are barter-able. The last being the only one, when traded, costs me nothing but a little time.
After the dust settled, crypto currencies would be a mainstay of trade and a primary currency I would guess