This will sound insane, but it's amazing. It's a niche fast food in West Africa that I make myself a few times a year.

First, get some bean flour. Any kind will do. Black eyed pea flour is best, but it's usually only something you find in an African food shop. Chic pea flour just as good, so is black bean flour.

Mix with salt, herbs, chicken bullion, and water into a dough and deep fry spoonfuls in a skillet into fritters.

Make up a batch of spicy tomato sauce. Lots of onions and oil and pepper.

Put those fritters in 6-10 inches (have someone else measure, guys) of the cheapest, thin baguette money can buy. Slather in sauce. Enjoy.

Entirely vegan if you want. Complete protein. Zesty, spicy deliciousness.

Online, look for kosai or chichena recipes for the fritters.

Peanut butter! Cheap, high calorie, with fats and proteins to balance the carbs. You can get jelly packets or even ketchup packets in a pinch (not quite as bad as it sounds) to keep it from getting repetitive.

Also consider rice and beans!

Peanut butter.

Just gonna say, get multivitamins.

Mashed chickpeas with vegan mayo is a good approximation of a tunafish sandwich.

Toast sandwich

https://en.wikipedia.org/wiki/Toast_sandwich

Buy boneless chicken in bulk, cook it in the oven, then slice it up and store in the fridge. Spread mayo on your bread then add sliced chicken and cheese. Toast the bread until the cheese is melted, add whatever greens you like (I use the same mixed greens or arugula that I purchase for my bunnies), slap the toasted slices together and eat one of the best damn homemade sandwiches ever.

It’s not the cheapest sandwich, but it’s really inexpensive to put together and delicious.

Peanutbutter and jelly.

Sardines are great in a sandwich and are healthy. I love sardines and thin sliced onions with some mayo as a sandwich, yum. Homemade hummus also cheap and healthy, and if you bought mayonnaise make a little slaw for that too.

Lentils on toast are good & healthy, not a sandwich but would leverage your bread.

Canned tuna is good and cheap.

Sweet pickles or barbecue sauce on the meat between two pieces of bread, idk it isn't bad. Definitely poverty food though.

1 little can will get you 2 or 3 sandwiches, and a big can will get you like 7 or 8.

If you have an air fryer, tofu slabs!

Slice a block of tofu short-ways into six to eight slices. Season on each side with oil and choice of seasoning. I use adoboe seasoning, garlic salt, paprika, and other savory flavors. Lay in a single layer in the air fryer and fry for 15 mins at 400 F, flipping with tongs halfway through. Put on bread, add condiments if you want, and eat. Leftover slices can be put into the fridge and either reheated or eaten as cold cuts.

Where I am, this works out to less than a dollar per sandwich, and makes a complete protein. Add some lettuce and tomato or other veg for more flavor, fiber, and vitamins if you can swing it.

Brown bread (bread made with rolled oats and mollasses) and baked beans has been one of my goto cheap bulk meals since I was little kid

Ill try to remember to post the recipes when I get home from work.

Milk whipped into mashed potatoes also makes a barebones meal that covers essential nutrition. And it is the season where you can buy a large bag of potatoes for cheap. (Taste and fibre content can be improved if you throw in a can of corn nibblets as well)

If you have access to a hot pot or oven, braising your own meat will be cheaper than cold cuts. Pork, whole chickens, and parts of turkey will be cheaper by the pound than their equivalent meat as a cold cut.

Peanut butter is one of the cheapest shelf stable foods, either per calorie or per gram of protein. It's obviously delicious with some sort of fruit jelly/jam. And the protein in peanuts complements the protein in bread, covers all the essential amino acids.

Spreadable or meltable cheeses are pretty delicious on toast, and can be supplemented with seasonings. I put cream cheese and everything bagel seasoning on my sourdough slices most mornings.

There are also a ton of delicious toppings for open face "sandwiches" or toast:

1. Avocado is a classic for a reason. If avocados are cheap near you, that can be an option.
2. Fresh tomatoes on toast are a classic in Spain for a reason, too.
3. Sardines or other canned fish/seafood, if you like that.
4. Mediterranean spreads like hummus, baba ganoush, muhammara, harissa, etc.
5. Shrimp, like gambas al ajillo or something similar, go really well on toast.
6. Roasted mushrooms

If you're baking your own bread, you can also try to shape some little bread bowls and fill them with soup. French onion soup takes some time but the ingredients are pretty cheap.

Not all of these options are ultra cheap, but many are flavorful enough that even small portions can work out to be really affordable on a per calorie basis, for stretching that budget with bread.

Op post a budget and how many days you need it to last. That's far more helpful.

Also what do you have to cook in? Stovetop? Oven? Microwave? Air fryer? Crockpot?

We can be far more helpful if we know some details

Hummus on its own or any and all parts of lettuce, tomato, rocket, roast peppers. Om sourdought foccacia is phenomenal

Zucchini sliced, green pepper, red pepper, onion, andoulie sausage if you can afford it. Coat in Italian seasoning or slap ya momma.

Air fry for 15 minutes. You can easily get two meals out of that

Sauerkraut with some mustard or honey.

Quick edit: or the mediterranean classic, bread with a dip of oil, vinegar, salt and pepper.

Peanut butter

Tomato. PB. Egg.

Idk if you go to Costco but I get a $5 rotisserie chicken.

Tomato sandwiches. Slice the tomatoes and season with salt and pepper and spread some mayo on the bread. Simple but delicious.

Peanut Butter. As a diabetic it's my go to when I want something sweet. As long as it's natural.

Also I don't know your kitchen situation but you can live off just Potatoes and they're filling. Microwave, bake, or air fryer. They are awesome in air fryer.

But how bad off are you if you can't even get cheese slices?

Like what's your budget? How many days before you get paid and how long do you need a extremely tight budget for?

Zero carb tortillas / pizza sauce / cheese/pepperoni is super cheep pizza.

Cast iron pan / fresh green beans / butter / garlic

Chicken / rice/broth soup

Rice is super cheap and can be used with a combination of ingredients. And makes quite a few meals. I miss being able to eat rice.

It depends on what your local store has at best prices, really. Depending on where you are, you might find anything at a locally better price.

Famously, though, the absolute cheapest sandwich that some people still love is a salt&pepper toast sandwich, literally softened butter on bread, toasted if you have a way to toast it, or maybe fried, with a sprinkle of salt and pepper, stuck between two other slices of bread. I have made it before and it's way better than it sounds. If you're wanting to push the price as low as possible, the salt and pepper might be gotten from fast food places' condiment stations, maybe even the butter/margerine as well if you have the right kind of place.

A mash sandwich is also deceptively good if you make good mash or have good condiments, and skin-on potatoes are almost always good nutritional value for money.

Beyond that, almost any sandwich can be bulked out with leafy greens for not much cost. Great iron in spinach. Lettuce other than iceburg is mild and nutriticious so helps almost any savory sandwich. Fiber helps you feel full too.

Slice your own cheese if you want to save money.

Also look for sales on tuna; tuna, mayo and spices makes a good sandwich, especially when fried in butter in a pan (and through in a slice of cheese if you're feeling indulgent).

The idea of vegan sandwiches is kinda lame to me; think the bread would overwhelm whatever you put inside it, but I can think of incorporating bread into vegan meals--like vegetarian chili with a good hunk of buttered bread is delcioius.

Toast sandwich

Some oddball favorites of mine are peanut butter and swiss cheese on sourdough. A hard crusty bread or rye with Vegemite ( goes a long way ) cheddar and onions. Any bread peanut butter and sugar ... And wheat bread with whatever leftovers.

sadly the cheapest meat are the "name brands" with nitrates in it. you can buy cheap sandwich meat from trader joes though.(instore brand). going vegan might be harder, as you will be nutrient deficient(you need supplments to compensate like b12).

Egg mayo/salad cream?