My thought, surely not new, is that for an indeterminate period, food, ammunition, firearms, tools, perhaps some other types of items, and possibly seeds if things go for more than a season or two, and in various areas will be priceless. My base scenario is that one-third of the people currently living paycheck to paycheck (77% of Americans, according to this guy in 2010*) will die. That means about 1/4 of the country, or 80 million. More elsewhere in the developed world. Meanwhile, hyperinflation will take hold, and owning PMs will be necessary.
After the reestablishment of commerce throughout the USA, (assuming it ceases in remote places), all of the items that we are buying now for a relatively high price, such as 1000 rds of .308 for, say, 1/4 of a price of an oz. of gold, will drop by 80% or more measured in terms of gold because global demand for base metals, food, and other necessities will remain very low, thanks to a population drop by 1/4 in the developed world and the impoverishment of that developed world. I estimate (don't quote me) base metal consumption will drop to 25% of what it has been. Probably concomitant with this would be an increase in consumption of metal for ammunition and other 'security' goods, but a drop in industrial consumption. Transporatation becomes more expensive because trucks now must travel by convoy with guards hired to fight off bandits, and the price of goods becomes correspoindingly more expensive.
Implication: one should have survivalist stuff, but not enough for Mad Max, and the rest of one's assets should be in PMs to deal with hyperinflation. Elsewhere it has been stated that the first thing to go in case of hyperinflation was clean water, I'll add.
Alternative scenario: commerce is not really interrupted, but ammunition costs do not drop by 75% because of increased domestic need and rise in cost of transport and operation of stores. In Cebu, in the Philippines, quite a corrupt place, every medium-sized shop/business hires a security guard. Potentially our (distant) future.
Likewise, a piece of gear on which I have had my eye is a 3rd gen. NVG. (I'm broke.) Without mad max, such is probably not worth buying.
*http://economicrot.blogspot.com/2010/09/77-of-americans-now-living-paycheck-to.html