Thing is (as gramps says) when the balloon goes up you can’t take a chunk of silver or gold to Walmart to buy anything. They’ll just look at you funny. How would they determine the value based on exactly what? Would our currency be worth anything?
Silver quarters.
Known coin. Easy to distinguish from non-silver. Value will be determined by new economy.
One Second After’s sequel, One Year After, posits that the new currency becomes silver quarters and 22LR ammo. I agree.
When the ballon goes up Walmart will not be open. At that point the best currency is heavy metals (lead, copper, silver and gold) supplemented by powder.