OK, as I promised, I'm putting up some posts just for people who are truly desperate, and this is one. Most of you in the US who are interested in budgeting aren't going to be interested in these extremes.
I'm starting with some assumptions. One is that you have access to some form of refrigeration and some means of cooking, even if it's just a cooler and a hot plate. Second, that you do have at least $50 a month for food. Third, that while you won't be at home at lunchtime (so want foods that don't need refrigeration or heating) but you aren't employed full time so have some extra time. Understand, this is NOT a healthy diet (and probably not adequate calories on some days), but it should keep you going long enough to get things back under control.
For breakfast the first day, a hot dog on a slice of the cheapest white bread you can find (from a day old bread store is even cheaper) should run you no more than $.03, and about $.09 for the cheapest brand of hot dog you can find. This will get you about 8 grams of protein. With this, have half a glass of milk for 4 more grams of protein at about $.08 (if regular milk is too expensive, check the prices on powdered milk to try to get this.) And have a very little bit of fruit or fruit juice. Our local store sells "lunchbox" apples and oranges for $.25 each, eat half of one of these. If you're large and/or do physical work, have an extra piece of bread or two as toast, but try to keep breakfast under $.35. For lunch, one to one and a half peanut butter sandwiches, the cheapest brand you can find, and the other half of the apple or orange should run you about $.25 to $.30.
During the day, find someplace that sells produce that's past its prime. Locally, I can get a small basket for $1. Get a couple of these, preferably things that can be eaten raw, will stay good for two or three days more, and will go well together. If nothing else, buy the cheapest bag of potatoes you can find. For supper, fix a pot of brown rice, about 1.25 cups dry weight (half a pound). This is about $.34 and should make about 4+ cups of cooked rice. Put a little oil in a non-stick skillet, heat to medium, and add half this rice (cool the rest and refrigerate for tomorrow). Break an egg (about $.10) and beat it a little before dribbling it over the rice, stirring it in the pan constantly. If your produce purchase includes anything that could go well in this (onion, pepper, squash, etc.) add about $.05 to $.10 worth when you add the egg. Stir until the egg bits are cooked thoroughly, salt and pepper and eat. First day's food consumed should be around $1.
For breakfast, warm up the leftover brown rice ($.17), and have with half a glass of milk ($.08) and, if you got a bit of fruit that can be eaten raw, have about $.10 worth for a total of $.35 for breakfast. If that's not quite enough, have a slice or two of toast, but try to keep it under $.40. For lunch, make a cheese sandwich with the cheap bread and the cheapest sliced cheese you can find, about $.20 for the sandwich, plus a bit more of your fruit. One to one-and-a-half sandwiches plus the fruit should stay under $.40.
Start supper early. Put a couple of quarts of water to boil. Assuming you have a few spices and such, a little cayenne or garlic powder can add some flavor, especially if you don't have some boullion to put in at this point. Add one and a quarter cup of brown rice, stir in, cover, and reduce to a simmer. Wash and cut up your cheap produce (potatoes, turnips, carrots, cabbage, peppers, onions, anything that will go well together in a soup), cutting out the bad spots. When the rice is about half cooked, add the vegetables, stir, cover and let simmer. If you need more water, add it now, then bring back to a boil before reducing to a simmer. Cook until the rice and vegetables are tender, then serve over a slice of your cheap white bread. The rice is about $.34, and the produce should have been no more than $1.50 total, and you should have a pot of soup big enough for three to four days. If you have 1/4 tonight over two slices of the cheap bread, you have a filling supper for about $.52. Your total for the second day is about $1.32. If you have a freezer, freeze two portions of this soup for later.
For the third day, dice two slices of bread ($.06), beat an egg ($.10), dice a cooked hot dog ($.09) and warm up a small skillet with just a little oil. Add the bread cubes and hot dog, and stir until warmed through, then add the egg. Cook like scrambled eggs until THOROUGHLY cooked. Serve with half a glass of milk ($.08) for a $.33 breakfast (I first saw something like this called "spornj" which I assume is Scandinavian.) For lunch, peanut butter sandwiches again, with half a piece of fruit for about $.35. During the day, buy a jar of the cheapest apple sauce you can find and the cheapest bag of potatoes. For supper, warm up leftover soup and serve over a couple of slices of the bread, $.52. Third day total, $1.20
For the fourth day, fix a big batch of oatmeal for breakfast ($.12), eat with half a glass of milk (.08) and a little applesauce (either in the oatmeal or separate-$.10) for about $.30. Lunch-cheese sandwiches, about $.30. For supper, start early and bring a couple of quarts of water, mixed with milk made from instant ($.25) and salt, pepper, and garlic powder, to a boil while you wash and dice up about 2 pounds of potatoes (leave the peels ON, but cut out bad spots.) Add the potato (about $.60) carefully, stir in, reduce to a simmer and cover. Check and stir about every five minutes. When the potatoes are soft, with the skins starting to fall off, remove from heat. This soup should be enough for about 3 suppers (about $.30 each), served over the cheap white bread (2 slices at $.06) and a little apple sauce ($.10) for a $.46 supper. Total for day 4, $1.06
So, you've eaten for 4 days for $4.58, and there are lots of variations on the cheap starch/legume meals and the least expensive fruits and veggies. Think with these kinds of cheap starchy meals, you can make it through 30 days for less than $50? At this rate, you could get through for less than $40.
Now, some suggestions. First, if things are THIS bad, look for help: food banks and other charities. But if you get some food from one of those sources, don't immediately blow your own food money on expensive stuff. Use their food to stretch yours, especially if they provide fruits and vegetables and meat, which this menu is VERY short on. With this supplement, you can increase your calories and protein some, stock up on a few extra good bargains in grains and legumes, and add a can of beef or chicken base to give those soups more flavor; plan for NEXT month when you may not have that help anymore.
If you can't get really cheap older produce, look at the best bargains in bags of frozen produce. I often find bags of frozen diced onions for $.60, not much more than what they'd cost fresh, and onions are not only particularly good for you, they really add flavor to boring soups. Applesauce is often very cheap. Powdered non-fat instant milk is often, though not always, cheaper than fresh. It's a good source of protein. Eggs are usually one of the cheapest proteins. There are usually brands of hot dogs and bologna for less than $1 for a package to add protein as well. Cabbage is often cheap. If you can get squash cheap, it's a filling vegetable. Overripe bananas. Some types of apples at certain times of the year.