I have an extra stash of cash for emergencies but wonder if that’ll help that much. With transactions stopped many stores will simply close. The food stores might stay open long enough to sell their perishables for cash but then what? If no one is able to pay bills, companies and agencies won't be sending out checks either. Even if they do the banks won't be open to process. After a short time only cash and a barter system will be in effect for the limited items available for purchase. Gas stations will sell gas for cash but experience assaults from panicked customers who won't accept cash only policies. Those with cash will be okay but only for a short time until stations begin to close completely due to civil unrest as customers desperate for fuel steal what's needed and more. Burglaries and robbery will go up as well and those with ammo might make it through a short time until chaos takes over entirely.
Won't be fun, that's for sure. But I still keep the stash. Hopefully it'll be of some help.
I have always purchased in bulk (it's cheaper that way) so at any given time, I have several weeks worth of food in the house as well as plenty of batteries, hygiene supplies, and whatnot. But let's face it, if the crap really hits the fan, those who "prepped" will very quickly be identified by those who didn't.
It will be like the "ant and the grasshopper" fable. The grasshoppers will quickly come to the ants for help. It will be quickly obvious who the "ants" are. They will be the ones that have generators running, lights on, etc. If you have cash (or gold) to buy goods at stores, people will follow you home to see where you live.
They will ask nicely at first. They will politely knock on your door, hat in hand. They will tell you about the pregnant wife (who might be lurking in the background with her hand on her belly) and the hungry young children who are playing in your front yard. Because you want to be neighborly, you will give them a little something and send them away. But they will be back. Oh yes, they will indeed be back.
You won't be as nice this time. You will make it clear that you are armed and that they are not welcome anymore. They will apologize and slink away. But not for good. Next time they will come with reinforcements, for word will have spread around that you have things. Things will get nastier. You might actually have to fire some warning shots over their heads to show that you mean business, and for a short time, they will disappear. But not for good.
Next time they come, it will be in the middle of the night and they will have flaming torches. You begin shooting at them for real but it is dark and there is no way you can get them all. They will keep coming, even if they have to climb over the dead bodies of those you already shot. And they will be angry, very angry. Eventually they will set the torches to your home and you will either have to evacuate or you will burn to death in your own home while others pillage whatever they can grab from your stash. Either way, it won't end well.
I guess the only way to really "prep" for something like this is to keep an extremely low profile. No generators. No lights. No going to the local store with a bar of gold or a stash of cash. Be very discreet and bury your empty food cans where nobody can find the. Pretend you are in the same situation as everybody else. In that manner, you should last a lot longer and might even survive until some semblance of law and order is restored.