I’ve never had to cook for 150, but closer to 50. My go to is spaghetti. I pre-cook all of the pasta; and when it’s time to serve, just putting it in boiling water for one or two minutes in batches heats it up perfectly. The sauce is probably the most expensive thing, but it’s ground beef and spaghetti sauce, with extra seasonings. It’s always a hit., and not a lot of stress.

We serve Rolls and a salad with it.

Large batch of Spaghetti pasta and large bath of penne pasta
Red sauce on the side
Meatballs on the side
Chicken (grilled/parmesan style)
Pesto on the side (but this is not at popular depending on the crowd)
Parmesan cheese

Large batch of romaine lettuce
Sides: shredded carrots, olives, tomatoes, what else do people put on their salad? cheese?
Dressing: Ranch and Italian, Olive oil
Parmesan cheese
Chicken (marinated grilled/parmesan style)

Garlic bread

So when you form a line, people can add what they want if they don't like meatballs, don't get it.

Desserts: brownies, cupcakes

Some variation of beans and rice will likely be the cheapest. Creole red beans and rice, cuban black beans and rice, Feijoada, lentil stew, bean soup...

If your budget is big enough for meat, large vats of beef stew are good - chuck, lots of onions, celery, carrot, tomatoes, potatoes, peas.

Chicken and dumplings or chicken pot pie - same idea as the beef stew - onions, celery, carrot, peas. Drop in dumplings or top with biscuit dough.

Gumbo with chicken and sausage.

Does it have to be easy to eat - so something like spaghetti (which is cheap) wouldn't work bc it's too messy w/o a table and silverware verses a styrofoam bowl of chili (which is easier to eat)?

Are you feeding the homeless for real or just mentioned that as an example? So logistics of disposable bakeware to hand out to people or do you want something that can be served hot in a buffet line ?

Can you get individual-sized disposable aluminum containers (they sell them at the Dollar Tree) and bake casserole /mac n cheese in each ?

Rice and beans will give people a bit of protein with their carbs. Chicken isn't that expensive either if you can add it in. I used to cook for Martha's kitchen for the homeless, and they were still concerned about nutrition even though the food was inexpensive. So even if you do pasta, please do see about adding an inexpensive bean or meat to it...

Don’t buy from a grocery store. Buy from a restaurant supply store. So much cheaper and already packaged in ginormous containers. Look at what is on sale too.

Bolognese sauce, just make it without the wine. If someone has a meat grinder buy inexpensive beef chuck and pork shoulder or butt whatever is cheapest. Bag of onions, carrots, garlic and a few cans of peeled tomatoes. The key to this tasting so good is to let it cook for several hours. Serve over pasta.

Chili is good too. It can be served over spaghetti with grated cheese and diced onions as toppings. It can be served on a hot dog. It can be served over tortilla chips. It can be served on its own in a bowl.

Potatoes are still cheap and filling, if you have enough people cooking they can bake them several hours ahead of time wrapped I foil. Put a towel in a cooler, load up with foil wrapped potatoes and cover with a towel. They stay hot. Serve with lots of topping options.

If it’s for the homeless look for things that are starchy, substantial and filling, also include some fruit as vitamin C is often hard to get. Get whatever fruit is on sale and cheapest.

Rice is another option, throw in some butter or cheese and whatever veggies are the cheapest.

Big trays of pasta. Something like a chicken casserole with egg noodles - heavy on the noodles & sauce, some chicken, add some vegetables like broccoli or zucchini. Bread on the side.

Pasta for sure. Beans and rice.

We feed the homeless in DC by cooking large vats of Rajma (kidney beans) and veggi Pulao.

1. Soups. Cheap and filling, can be very tasty.
2. Carbs are cheap too, and you can prepare big trays. Cheese blintzes, potato pierogis, meat pies (which don't need that much meat), dumplings with meat and cabbage. Various pasta dishes - baked ziti, etc.
3. Sandwiches

Ask for donations from grocery stores/restaurants if it is a charity event.

Otherwise, and with inflation this may be more expensive than it used to be, but do a breakfast: giant bag of oatmeal or grits, scrambled eggs from powder, bulk scrapple or other cheap breakfast meat, toasted sliced bread, reconstituted orange juice, coffee, and your cheapest fruit (bananas?). Hand out peanut butter sandwiches and bananas for later.

Chili would be my go-to, but could be weird in summer. I'd still eat it, but some people might not.

Pasta- you can make huge batches, maybe two different kinds, like one with pesto and one bolognese.

Meatballs- Bulk, pre-made, served with choice of bread or pasta or mashed potatoes or something. Turkey will be cheaper than beef.

Lentils- I don't know with what, just thinking of things that can be tasty but also made in big crocks.

For veggies you could do big trays/bowls of salads or lightly steamed vegetables (buy frozen in bulk, season with sea salt and a little butter)

Or you could always do just a massive batch of DCUM's fav, NYT chicken shawarma. I've made it in 6lb batches so why not bigger? Slice, skewer (or not), serve with pita/rice and salad.

Make sandwiches, pizza when you can get a $5-7 deal (or call the store and see if they will give you a deal), hot dogs

I am talking 50-150 people in a context where getting food out matters. Think feeding the homeless - want the food to be good and tasty of course, but cost is a big issue.

Please give suggestions if you have experience cooking in this context!