I have seen a lot of posts about how it is more expensive to eat healthy than to eat unhealthy meals and I know there are a lot of KOS people without jobs right now. I have an unusual way of thinking about how to eat cheap, but it is reasonably healthy and much less expensive than any prepared foods.
The USDA has their food pyramid and before that it was the food groups. They classify everything by servings, but I find that the serving model is really hard to use. Instead I go by the pound which people can easily relate to actual food prices and how much they need to eat.
The goal is to have meals costing about $1/per meal so about $60/month. Any prepared foods are generally more expensive than this. Typically at least $3/meal and McDonalds is extremely expensive at $6/meal
Generally speaking as an adult you need protein, carbs, fat and vitamins/minerals. You also need about 1200-1800 calories if you don't exercise too much. I'm typically on the upper end of the scale and I'll primarily discuss the food as it relates to me.
I divide food into the following groups
Protein 1/4 pound per meal
Carbs 1/4-1/2 pound per meal
Vitamins/minerals 1/8-1/4 pound per meal
For protein and vitamins/minerals, the target is about 1/4 pound each and for carbs 1/2 pound for each meal. This will leave you feeling full. The advantage of carbs is that they are extremely cheap but arent really healthy in any way. Protein and vitamins and minerals are more expensive.
When shopping for protein the target is any meat that is 1.50/lb or less. In my area eggs are around 1.50 for a dozen which is about 1.5 pounds. Chicken thighs are around .69 cents, whole chicken is about .99 cents. Ground beef at 1.89/pound is usually too expensive, but used as flavoring it is ok. I can often find bulk pork chops at 1.50/pound. This means for each meal, you can get your protein for about .25. I did get to the level of getting an average weight of bone in whole chickens and the like but that may be too much for the average person.
Also, bones should be used to make chicken stock/pork stock which can make soups that fulfill your taste buds (get the taste of meat) at a fraction of the price.
Often times I would use a more expensive piece of meat as flavoring and then have the primary meal be beans. So maybe a small piece of catfish (3.99/lb) along with beans and tortillas.
Beans are the ultimate staple as they are virtually free if bought in 20 lb bags. Beans flavored with pork back will take you a long way.
cheese runs around $2.50 a pound but if you just use it for flavoring you dont need much at all.
Carbs are your fuel and they can give you the energy you need but little else. The least expensive carbs are flour, rice and potatoes. Potatoes can be gotten in 20 lb bags for $5. Flour comes in 50 pound bags for $30 and rice comes in $20 pound bags for $15. When I talk about the weight of carbs, it is the weight after cooking. Rice when cooked weighs about 1/2 pound per cup and rice is about 1/2 pound per cup raw. 1/2 pound of raw rice makes about 1-1.5 pounds of cooked rice. So in a 20 pound bag that is about 40-60 meals worth of rice. This makes around .25-.40 per meal for the carbs.
Prepared pasta, bread and tortillas are extremely expensive while flour is extremely inexpensive. However making the above is labor intensive. when I was really poor but had a lot of time I made all of these from scratch. The cost comes out to be similar to rice and potatoes.
We just dont need that much in the way of vegetables, but I try to eat veggies in at least one meal per day. Most people dont eat vegetables in any meaningful way every day. However if you consider it to be important, a 1/4 pound per meal will be more than what most people eat. Vegetables are tricky because their price varies so much based on season. I used to buy my veggies from a farmers market that would sell a 2 gallon bucket of veggies for $1. I typically would get at least 1-2 pounds. If the bucket had potatoes it would be like 10 pounds. In the city I live in now I havent seen deals like that, but I do see veggies going on sale when they are in season and the farmers market have similar deals, but maybe not as large a bucket. When buying fruits/veggies you can pretty much only buy whatever is onsale.
Skip lettuce and the like in favor of ones that actually have nutritional value, broccoli, spinach, carrots,tomatoes etc.
Frozen veggies can be pretty inexpensive and for things like spinach that I cooked with a bit of meat, frozen was ok. Your target for veggies is between $.50-$2 per pound. Bananas, canteloupe, and even some berries when in season fit. The more expensive ones you will eat less of and bulk up with the ones under $1/pound
Recipe wise I found I only needed about 15 different recipes to not feel like I was eating the same thing all the time.
Here are a few basic sauces that can give you good variety:
Chinese - oyster sauce - makes broccoli beef
teriyaki style (soy, garlic, sugar, rice wine)
Tomato sauces -
cheese sauces (alfredo and the like - changing the cheese radically changes the sauce)
fruit sauce (mango chutney)
salsa based sauces
There are just a few stocks to use as the flavoring for sauces or soups
Here are some inexpensive recipe titles that I use on a regular basis. You can find actual recipes on the net
Eggs any style - poached, scrambled, hard boiled
Homemade pasta (mostly fettucini because it is the easiest)
any meat marinated teriyaki style
refried (pinto) beans
Chili (uses very little meat, mostly beans)
french toast (use bread that is getting stale)
grilled fish with garlic butter
tortilla with Jam (as dessert)
rice krispy treats
Homemade yogurt with fruit/vanilla (put gallon of milk on top of fridge with live cultures)
pumpkin pie (happens to be extremely cheap to make)
Here are the spices I use most often
tarragon (roast chicken)
bay leaves (gumbo,jambalaya)
basil - red sauces
cayenne pepper (gumbo/jambalaya)