I think that there are people on here justifying buying readymeals unnecessarily.
Even as a student with £11 per week to spend on transport, hygiene articles and food altogether I cooked from scratch every day, because it was cheaper. And Halls facilities were not great - we used to have maybe one or two working hob rings, yes, an oven (which was gross, so rarely used) and fridge and freezer space was limited to one drawer each, as well as only one small hanging cupboard for all of our crockery and ingredients - so very limited storage. Plus, as we were starting out, we had very little equipment.
Everyone can build up a stock of herbs and spices over time. You don't buy five at once, but one every two weeks or so will easily amass a good amount of basic herbs and spices within half a year, even with replacement buying.
People here are saying that they would have to live on the same food for a week - well, no, with a fridge you can already stretch that to every other day and most things are freezable, so last for a good few months. Pizza is a great example. Pizza dough might, on paper, take a long time, but in practice you spend 3.5h out of 4 basically ignoring the dough as it proves. You wrap the portioned and rolled dough (we used to use bottles for that instead of rolling pins) into clingfilm - store it for a time you want a quick fix pizza. You use passata, salt, pepper and perhaps even some herbes de provence, simple cheddar cheese and there you have a decent, basic pizza.
We chucked everything leftover on it - from a tiny portion of chilli we had left from a dinner that week, some egg, some defrosted spinach and perhaps an egg, or more traditional bits like offcuts from bell peppers, the last two salami slices, the last rasher of bacon.
And if we look at traditional British food, so much of it was designed for cheap, wholesome food made with tiny bits of leftovers.
It is absolutely possible to make almost anything from scratch cheaper than buying ready-made, too. The lasgana example on the first page assumed 1kg of meat - you'd need a LOT of ready meals to get that much meat together; most barely have any in them. Most ready meals either have lots of water in them or lots of starch to give the impression of being more than they are.
It's also why they will leave you hungry again soon after, while a decent portion of something homemade will likely allow you to comfortably only have one or two meals a day without being hungry or nutritionally underfed.
The only argument there is here is that people don't have the skills, but that can and should be countered with access to the internet and therefore a world of free recipes, step-by step instructions, video guidance and even websites which will find a recipe for whatever random items you have left in your cupboard.
Sorry, it just doesn't wash with me, and I have been poor for many years.