Except they are loaded up with salt, fat and other ****. Nothing stopping you from buying a whole chicken and cooking it yourself (takes about 40 minutes). Less convenient, but better for you. As others have said, eggs, tinned fish, I'll add milk to that list. It's about $1 a litre here and is excellent at just about everything. Get a cheaper of beef (or mutton, or even pork), dice it up and throw it in a cast iron pot with a bunch of veggies (potato, carrot, parsnip, tomato, celery), beans, even some pearl barley add a bit of liquid/stock and cook it for like 2 hours in the oven on a low heat, divide it up and keep it in the fridge or freezer and heat up as needed. Also, look into traditional types of street food/peasant food from around the world. It's generally very cheap and can be very nutritious. I first made a paella about 5 years ago and I've tweaked it over time into something that tastes fantastic and is genuinely healthy, and depending on what you put in it can be made cheap as hell. Also, replying to this thread has made me ridiculously hungry.
I buy a large chicken from sainsburys for £6 and break it up which gives me enough chicken for 8-9 meals. Use it to make numerous dishes like curries, sweet and sour, paprikash, black bean and peppers, stir frys etc.
red leaf lettuce greens/collard greens canned sardines tomatoes - even cheaper to grow they like weeds with little help
I grow a lot of greens in the fall and collards are one of my favorites. My garden is also loaded with several types of lettuce and other salad greens in the fall and spring. I must have had close to 100 lbs. of tomatoes this spring and early summer that I harvested. If you want cheap, healthy food, grow you own vegetables. The initial start up cost is not all that bad depending on how large a plot you want, but it more than pays for itself after a couple seasons of harvests.
Watch the sugar and sodium content. Stick to a cereal that's high in fibre and low in sugar and sodium.
Yes always but honestly cereal replacing a meal is almost always gonna be lower in all those than an actual meal unless ur dumping a truck load of extra sugar on it like i used to do as a kid with cheerios