I live on my own now and shop daily. I walk to the shops and only buy what I can fit in my basket/back pack.
I help myself to supermarket leftovers at the food bank and community fridge. I'm told it gets thrown out if not eaten or possibly fed to pigs. There are often ripe bananas and M&S sourdough bread.
A few weeks ago I picked up a huge box of chanterelles from Lithuania
I don't want all the plastic packaging so buy loose fruit and vegetables and I use and also volunteer at our local farm /community store for rice, pasta, oats, lentils etc. and washing up liquid, washing liquid, hand soap etc.from the refillery.
I prefer real soap and it lasts 10 times as long
I shop in Lidl too and like their bargains.
As for own brands: toilet paper, tissues, beans and tomatoes are fine but I was given some co-op tea and it was horrid.

I think I eat well and cheaply.