No, there is no one cut-to-fit, made-to-order answer to the question “What Do I Use As Post-Event Currency?”...
The post-event economy will dictate what the medium of exchange is, but you can pretty much expect it to look like this:
What do you want to trade for? WHATEVER I WANT AT THAT MOMENT.
What do you want to trade with? WHATEVER ELSE YOU’LL ACCEPT.
“Hey, Fellow Survivor, I see you have a case of MRE’s, I’ll trade you these nice pieces of junk silver for it, deal?”
“Gibsme fifteen minutes with your teenage daughter, or no deal, cracker...”
(NOTE: I paraphrased that transaction from a Selco article, so there...)
You mean that stash of Bitcoins I am sitting on for when TSHTF won’t work???
Dang!