Here is something you may want to look into as a trade good, pre-64 US dimes, nickels, and quarters. These coins have silver in them, and as such could be used to trade for things like food and ammo. The easiest way to get them is to just buy them, but this will be expensive with current precious metal prices. The one's I personally have are ones that I have gotten in my change. Any way you do it, this is a trade option you should look into.