I live in a major U.S. city. In many disaster scenarios, the city is the last place you want to be.
But I didn’t understand the original post as a prepper scenario. I thought Craig6 was referring to how much cash we should carry with us to get through a sudden emergency. That’s an interesting question, and I should certainly do a better job keeping cash on hand. The 3-month rule for personal hardship makes perfect sense, but maybe not as much during the zombie apocalypse.
Exactly. Lots of barter goods and a bit of shiny metal. 
Different situations for different people are definitely a factor
As much as being in a city is not desirable, I would even-less like being caught in traffic on a city street unable to get anywhere except on foot amongst the masses. If you know what’s coming long enough before everybody else and can get out of the city, and to somewhere else where the situation will be better, and you’ll have security and supplies, YES
I picture hurricane evacuation traffic and the epic level of stuck people get and would rather stay in a city apartment than be stuck in that is all
Society will will likely collapse, and those with large cash denominations will have difficulty making change or keeping it safe; likewise with precious metals.
One might consider something more valuable in terms of comfort in the barter arena.
Alcohol, cigarettes, motor oil, fuel of all sorts, and batteries, may convert you into a god-like figure during bad times.
Keep in mind value is relative.
Short-term nastiness with family I have to defend; bullion is for air transport, and cash is to cover the fuel. As long as cash works, no fifties or hundreds keep things within the mental equivalent of general society. After that, all you can do is live well in your home on what you have stored with the neighbors, family & friends, you can depend upon locally. Don’t forget, fast friends with medicos is always a plus if not a pure necessity. In fact, BE a medico to whatever level you can achieve and teach your children/spouse well.
Beyond that, now, before the worst descends, do everything you can to be involved in your communities and seek to build/continue genteel society. It takes all of us, it takes villages, it takes countries. Good luck, good journeys, and may God (however you relate to HER) keep you and bless you.
FWIW, while you’re planning evacuation ahead of, during our following a natural disaster, consider the extended reach of shortages beyond the disaster itself.
When hurricane Harvey slammed the Louisiana-Texas coast in 2017 and hurricane Katrina in 2005, thousands who evacuated to the north ran out of the fuel they had in their tanks and sucked all the service stations dry along the way. Many were forced to abandon their vehicles or spend a few days in them until the National Guard came to the rescue.
In that kind of calamity — global, national, regional, or local — I wouldn’t even think about leaving the house for a couple weeks unless physically in danger. So I would have no particular interest in cash. More important would be means to learn what’s going on and what to expect going forward. Without power and internet, I would not expect much commerce to be functioning in many ways — more than simply ATM card impotence.
For end times/zombie invasion prepping, I think the idea of several months wages is a useful scale. Not so much that it is supposed to pay for “survival” or regular life for that period of time, but to be a portion of personal wealth a person might be able to set aside — to endure system problems for a period, and a useful hedge for regular purposes in regular hard times. Or some similar kind of “portioning” — like 20% of net worth as insured bank deposits and 10% of bank deposits as cash literally in-hand. Or whatever seems a prudent plan for personal financial resilience by keeping some of your eggs out of the same basket of vulnerability.
Just walking around every day, inflation has also drifted me from carrying $20 to wanting $100 immediately available for the unexpected. While $100 bills are certainly compact, I don’t think they are readily tendered in most places even normal times. Whether $100 or $10,000 — I would not want very much cash reserve to be in bills larger than $20s unless compact was more important than liquidity.
Living in a large city is like being in a large building: Always know your exits.
That doesn’t mean I’m going to bolt every time the power goes out (which it often does), but I think it would be careless of me if I didn’t have some safe destinations outside the city and multiple ways to get there. The real nightmare scenario involves an urgent, unexpected catastrophe but my family is spread out all over town.
Anyway, I didn’t mean to hijack this thread and talk about the pros & cons of urban living. This is just where my head went, given the hypothetical in the original post. If electronic means of purchasing went down for a week or more, I could see that leading to civil unrest. Most large urban areas are not sustainable without daily feats of logistics, so this could be a time to initiate the Plissken Protocol. Do I have the means to make the trip if credit cards don’t work? That’s the question.
But what would the new currency be in a zombie apocalypse? Is that mattress full of cash going to be good for anything except burning?
One Popular Series on the Si Fi Channel suggested Oxycontin and Antibiotics (“Z Nation”). I would suspect Ammo would be a large one at first, guns, MRE’s, Alcohol, Knives, anything that benefits one in fighting the undead or survive the undead. Depending on the cause of the dead rising Holy Water, Crosses, Masks or Hazmat gear could be a currency.
For most people though, there are some significant practical and legal hurdles to stocking oxy and antibiotics.
I honestly don’t think ammo will be very high, as I think most people will actually use very little.
But yeah alcohol, tobacco, firearms themselves, any medical ability and supplies, soap, hygiene, water filtration, stable foods, TP, fuel, batteries, ability to charge battery powered devices maybe, construction and repair material and tools…comms. Amateur radio operators, rigs, antennas
Who knows? The challenge to “end times” scenarios — really anything beyond weeks and local region — is that we really cannot know. That’s why splitting your eggs into multiple baskets matters, but each basket of financial reserve/resilience needs to contain enough to matter before it can be considered currency.
Maybe cash will work, but $100 won’t go far. Maybe banks or equity markets will reopen, maybe they won’t. Maybe gold doubloons work, but will you get change for a gallon of gas? Maybe “stuff” — medicine, wrenches, ammo, TP, solar panels, dried food, radios — but if you only have enough for personal needs it is not available as currency. Maybe you have equity in real estate, but it’s up in flames or the barbarians take it. Maybe your equity is tied up in a motor vehicle, which has no utility after EMP takes it down.
The point is — without diversity and depth, vulnerability to whatever calamity actually does strike you will be high. Most folks don’t have the resources to cover every contingency. So one needs to make choices and go deep enough to matter on the most likely, or most worrisome, or most practical, before going broader. And then go broad enough to matter before going deeper.
In a true apocalyptic scenario, I think the most valuable thing any of us can have are friends.
I think there are a lot of potentially serious but less than apocalyptic scenarios that would make having extra cash on hand important.
I lived through one over a dozen years ago where the money in my bank account disappeared. I had to show the bank a previous paper statement and tell them what I had spent money on since the statement for them to figure out how much they were supposed to have in my bank account! They knew their computers were having a problem with a handful of customers accounts but had no idea what happened to the money or how much was supposed to be there. I was anti credit cards at the time and it was a lean couple of weeks working to get my account restored. Now a lot of banks don’t even send paper statements so I make sure to get receipts with my balance on them from ATM withdrawals and take screen shots of my balance when online banking. Anything stored in a computer can be made to disappear with a few keystrokes.
Imagine hackers taking down the big banks and credit card companies. A little cash could go a long way towards helping your family and friends get by while everything gets sorted out.
It was suggested to me years ago that a roll of quarters might well be worth more than a roll of $100 bills.
In any kind of emergency that causes a power outage, the mechanical vending machines will keep working, but not those electronic marvels.
I keep greenbacks and coins available.
We have always kept a change jar and 2 times a year we would turn it in to the bank and have $115.00 in the jar and we use it for mad money. Now we keep all our change. 
about 400
I keep between $800-$1200 in various denominations (mix of coin jars & bills) stashed around the house.
2 weeks of packaged food & bottled water on hand for shorter scenarios. Additional food, seeds, ammo reserves are at the bugout location-
46 acres an hour out of town with solar & wind power, well water, a stocked lake & only 2 neighbors in a mile. The only vehicular entrance is an unmarked single lane gravel drive. Not only do I have trees rigged to fall across it, but the first .3 mile are straight & uphill. Leading to a deer hide at the 90° blind turn. I have given a sealed envelope with printed directions/map to a few close friends including EMTs, avid hunters, & fellow tradesmen.
I have a '76 Monaco (no computer chips) with a tow package & full tank to get the family there.
Sounds like your ready Brother. Best of luck to you and yours.
Why thank you Sir.
People have called me everything from psycho, to paranoid, to prepared. Not that I care what others say. They can make their own plans.
It definitely helps that my family has been in this area for generations.