I am lucky that my income to expenses is a good ratio so I can buy what I want without undue hardship but I cringe because I used to feed myself for about half the money.

I do buy items in bulk when the bulk unit price is significantly lower if it will keep and I will use it eventually. I will also try to get these items while they are on sale. This is a one time high expenditure that pays off in the long run and unfortunately the people who need to do this most are the ones who can't afford the extra expense at one time of buying bulk. I do this with things like rice, beans (I'm vegetarian so I'm not eating beans because I can't afford anything else, it's a big part of my diet). Also things like flour, salt, pepper, anything that doesn't easily spoil and will get used eventually.

I also allow the store to track the fuck out of me on their app by clipping store coupons. Unfortunately this is a necessary evil because it usually saves me $10 to $15 per week.

With fruits and vegetables, buying what's in season during the growing months saves a lot and buying frozen vegetables instead of fresh has the same or better nutritional profile but can be much cheaper.