Milk. Great Value’s brand just tastes so darned awful for some reason I can’t place. I live in the midwest, and Prairie Farms is pretty common as a brand here.
There are some others, many dairy products now that I think about it, but there’s also some medicines like Mucinex which I prefer to use over generic brands. I’m otherwise not very picky.
Here in the South the store brands are coming from the same processor as the ones that cost 3x. Check the codes by the date that are used for traceability.