I once read a book for people in poverty, written by someone in the middle class, containing real-life tips for saving pennies and such. It’s all fantastic advice: buy in bulk, buy a lot when there’s a sale on, hand-wash everything you can, make sure you keep up on vehicle and indoor filter maintenance.My mother accumulated a decades' supply of food that went bad--cans that corroded, etc.--because she bought things that were on sale and/or in bulk. It's more cost effective to buy what you need (she says as much in the next paragraph).
More to her overall point: it's also terrible advice to hand-wash everything. It's more efficient, if you have an efficient washing machine, to machine-wash. But an efficient washing machine costs money, is out of reach to very poor people, who thus can't benefit from its efficiencies.
Like the author, I've spent a lot of money buying cheaper things I have to replace sooner. I'm not poor so it doesn't break me, but I can back up her point that it does cost more money. I've probably bought the cheaper toaster that just ends up breaking faster or some other appliance that doesn't meet my needs and has to be replaced. I just made the mistake of buying the wrong case for my iPad and had to order another one. I think in everyone's life there's that category of expenses for mistakes and not knowing then what you do now. But when you're poor, those mistakes can be existential threats.
My mother always advocated for buying the cheapest thing (if not many of the cheapest things). She could never see the benefit of spending a little more money upfront to get something that worked. When I was a child, she bought me numerous ill-fitting swimsuits instead of one decent one. As an adult just out of grad school, she berated me for buying a decent (but not expensive) new suit to interview in instead of the cheapest second-hand one I could find. She would continue to try to foist upon me thrift-store finds that just didn't fit; the idea was that I should try to make them work, because the price was right. It was an uphill battle to get my parents a functioning, mid-range vacuum cleaner that works very well in place of the dozen shitty ones littering the house.