Not sure about how things will go right away. I think most folks will try to use what cash they have on hand for as long as they can, or until they run out. Shouldn't take more than a week. I seriously doubt most folks have any PM's. My bet is no more than 10% of folks and probably no more than half of those have more than $100 or so.
For barter, how many sheeple is gonna have much of anything useful to trade. Food, seeds, tools, doubtful. At best you might be able to get some labor from them but then you take a chance on them figuring out that you have stuff to live on and will be back to try and liberate it.