It was a good while back now but when I first had DS I was a single parent living on income support. I had a council house, but it was a big 1970s-built concrete thing with an uninsulated flat roof, draughty single-glazed windows, one big space downstairs (lounge, dining room and kitchen all open) and no heating upstairs despite 3 bedrooms and a bathroom. Because of this it was pretty much impossible to heat it in the winter.
DS and I used to spend hours in the library (walkable) or at the local shopping centre (there was a free bus at the time as it hadn't been open long) just sitting and reading, or playing quietly, just cos it was warmer than being in our house.
When we got home I would make a "den" in the living room out of blankets, duvets and pillows, put the heating on for 20 minutes for hot water, bath him in the kitchen sink then we'd both snuggle in the "den" for the night.
Foodwise it was value beans on toast and cereal most days, or jacket potatoes. I'd make soup with cheap veg and bulk it out with pearl barley. Baked or mashed spuds, pasta bake made with ketchup rather than proper sauce, bolognese or stew once a week depending what cheap meat I could get.
We lived like that for the best part of 4 years. Not the best of times, but we did get through it. Once he was at school I was able to find work and it gradually got better from there.
These days there is always food in the cupboards here cos I too remember what it was like to not have any.