Interesting re budget for prisoners - I can easily shop for three adults on £60pw and could cut back more in terms of cheaper choices. We eat well on this. Today I'll have cereal, a cake, wrap with cream cheese, cucumber and tomatoes on side, apple, clementine, gnocchi with a creamy tomato and aubergine sauce with a green veg on side. In the day, DH have a cake, something like egg/beans on toast for lunch with tomato, a banana and yogurt after tea. DD has last night's leftovers, a banana and nuts for the day.
Something like WW2 will dictate shortages of certain goods, but people adapted growing their own veggies, different recipes like carrot cake etc.
If we really didn't have the money, clothes would be kept longer - no throwing something because it had a stain on it, and sewing up patches. We spend £135pm here on gas and electric, but if we couldn't afford that or it wasn't available, we'd just have to do without. Both sets of grandparents didn't have heating, one had a gas fire, the other an open fire and a mini log stove thing in the kitchen.
We want far more than many had years ago, most people have a landline and mobile phone, tvs, computers/laptops etc, cars, pets, holidays, subscriptions, going to classes, eating out and there are lots of extras we have like garden furniture, plants.