As others have said, the important things are having money saved and knowing how to have an inexpensive lifestyle. Someone said that you should live an inexpensive lifestyle so that you can get those savings started and build the habits and knowledge you need to live inexpensively. I agree with this and in fact I have been doing it for a while.
My total expense for one month of living is 600 dollars.
I have around six thousand dollars saved right now (which is very little, but I've just started saving and working). So I could last around a year without any income.
I pay 400 dollars for rent. I live in the city and share a two bedroom apartment with four other people. The key to making this arrangement work is to live with nice people. I've managed to find nice people to live with and I enjoy it. If you want to really save money on shelter, build a passive house. Please look at my comment history before commenting that houses are expensive.
My food costs 70 dollars per month to meet all nutritional requirements, and in really tough times I could cut my protein levels in half (still getting more complete protein than most Americans probably) and bring that cost down to 25 dollars per month. I've put a lot of thought into my diet system, and it's nice to finally have an excuse to discuss it.
The human body requires carbohydrates, (complete) protein, fat, essential fats, essential vitamins, fiber and water. Some of you may be familiar with Soylent -- I was a big proponent of Soylent when it first came out. Soylent turned out to have a high GI, a high cost and a high impact on the environment. But the mentality of Soylent is still rock solid: the human body is not magic. If you give the human body the things I listed above, it will function properly. So if you are trying to optimize your diet, you first need to understand what the minimum viable diet looks like. Now that we know what MVD consists of, we need to find the cheapest sources for those things -- the cheapest sources that truly meet all quality and nutrition requirements.
For protein I eat canned chicken. There are probably better solutions but I haven't seen them. It's lean, complete protein and it's cheap. I get a months supply at Costco for 30 to 40 dollars. It also helps me meet my cholesterol requirements.
For carbohydrates and fiber I eat whole wheat bread. You can buy fifty pounds of whole wheat flour at Costco for around 13 dollars. The salt and sugar are so cheap in bulk that they aren't worth mentioning. The yeast comes in dense dry packs, 5 dollars for many months worth. Just open the dry pack and put it in a sealed container and pop that in the freezer. You can add oil for good fat. all you need to do is put these ingredients into a bread machine. If you don't have a bread machine you can buy one at your local thrift store. I bought mine that way and it's been going strong. It only cost 7 dollars. I see a bread machine almost every single time I walk into a thrift store, which is quite often. They are rarely more than 10 dollars. The cost to make a large, very dense, 2000 calorie loaf of delicious whole wheat bread (real whole wheat, not the hybrid garbage you would find in a super market) is 50 cents at the highest. This includes the cost of water and the electricity to run the machine at a cost of 15 cents per kWh. To store my flour I have food-grade buckets with so-called Gamma lids. Its extremely convenient.
For essential vitamins I take a complete multi-vitamin. Just to be extra cautious, I eat a vegetable here and there. There is very little doubt that I get all the vitamins I need. The vitamins I get from Costco -- they are beyond cheap.
For essential fats I take fish oil, which provide Omega 3 EFAs, and for Omega 6 my whole wheat flour is enough. It would be trivial to adjust my EFA levels up or down if I wanted. The fish oil is also from Costco and is very cheap indeed.
Some might look at this diet and wonder how anyone could sustain it for long periods of time. I wonder how anyone does anything else. If you read up on heart disease I think that you will view this diet in a much better light. Most diets are high in saturated fat -- anything with saturated fat will stay with you. A portion of the food will literally stay with you, inside you -- it will collect on the inside of your arteries and cause them to harden. Then your arteries will crack, bleed and clot causing you to die in a very painful manner. This diet is very, very low in saturated fat. It has an extraordinarily good glycemic index. It is not only the best way to eat on a diet, it is a very, very good way to eat in general. If I had a billion dollars, I wouldn't change it. This dual purpose makes me very happy with my diet. I've been using it for almost a year and I feel great.
edit:
if you live in an apartment, consider a portable washing machine. before, i had to pay four dollars to do a load of laundry in the machines that my complex provides. i dont own or want to own a car, and even if i did i wouldnt want to take my clothes to a laundromat. it turns out that they make washing machines for use inside an apartment. i have a 3 cubic foot model that hooks up under my bathroom sink. its literally ten times cheaper. i also air dry my clothes, which saves even more money. air drying clothes is amazing and i have no idea why it isnt done more in the US. its free and works just as well as machine drying. it doesnt require any more work or time (human engagement time) than machine drying, either.