Earlier quoted context omitted.
I think you mean buying in bulk. Buying in bulk is great but often not because if it is food it might go bad before you eat it and if you are poor your limited on space... so huge packs of items don't fit well in your tiny space. Plus the up front cost is a real killer since the money is saved over time. And if you have more of something you might end up using more because it's convenient. And finally if you are spli…
There's a subtle difference between "buying in bulk" and "keeping a reasonable stock". I grew up in a quite poor family and my parents are terrible with money. One thing that frustrated me to no end is that they would almost never buy something ahead of time. An item would literally have to run out before they'd consider buying its replacement, which meant I'd regularly get in the shower in the morning to find there…
I see this at a lot at my local 7-11, many poorer people do a lot of their grocery shopping there even though an aldi is 5 minutes walk away (so it's actually closer for some of them, literally across the road) and three other supermarkets are under 15 minutes walk. I suspect there is some sort of psychological effect (possibly from advertising) that is compelling them to go to 7-11 instead of somewhere cheaper and that they aren't making a conscious financial decision.