I keep my shopping budget under £30 a week, just me, food and household, the surplus is the following weeks cafe fund. I eat well out of that, though being time rich I can be shopping in the right place at the right time to get the best value. Though the bargains from markets as they're packing up has declined, traders are more inclined to put stuff back in the van than they used to be. I try not to eat too much packaged convenience food, I'm not always successful, I get fooled into thinking it's cheap and it rarely is. Growing up in a large family on a limited budget, lunch was always related to the previous days dinner. I was well into adulthood before I realised that wasn't universal. It's probably the most economical use of food and so ingrained I don't think I could do otherwise if I wanted to.