I think trade and bartering will take over for a while, just until order can be established.
Really money is a representation of the stuff you do have. So rather than carry around a lot of stuff, you have money to represent that. With the apocalypse, money will be wiped out, because people might not really recognize its use. What good would money do you if you do not have stores or if people who want it? Today, money works because we have places where it is useful. We have places we can get things if we have money. Post apocalypse, you really can?t find money accepting places and that money won?t do you any good just sitting around.
I think in time, money might come back, but not until order is reestablished. Until then it will be all trade, because trade makes sense. You carry what you have, and if you need something else you trade with another person. It is a bit safer because you have something right now, rather than money that just gives you the potential to buy something.
Trading could give you food or clothing, while money gives you sheets of colored coins and fiber.