your not always going to have everything you need no matter how hard you prep, so what will you use for trade? I good barter currency should be small, light weight, have daily comfort or survival value, and be cheep to acquire right now. keep it this way so you can carry a large variety of items when you go out looking to trade. some things I'm overstocking for trade. Basic first-aid items: pain killers, cold & allergy meds, antiseptics/antibiotics... Food items: sugar, chocolate, rice, salt(think meat preservation) Gear: fishing line, fish hooks and the like, fire stuff(matches/lighters..ect), .22lr ammo I would recommend saving any gold for the reconstruction phase so you have some wealth when the economy starts to stabilize and there is a reliable currency in the system.