Often it is not just about types of food but where you can go to buy it.

Which depends heavily on region (the USA is ENORMOUS, literally thousands of miles separates e.g. Texas from New York City), but Trader Joe's often has high quality foods for lower prices (and such variety too! Not so much week to week but different than regular stores, like international foods, and more optimal for a single person portions, but still has things like packs of frozen chicken great for families). But "very little money" might exclude that, for a family and especially one that still needs to visit another store bc TJ's does not have everything (I wouldn't purchase toilet paper there, as it would be more expensive than regular grocery stores iirc), so the time and travel burden of visiting multiple stores can be prohibitive.

At which point I think of Aldi's (owned by same parent company, in Germany iirc) - if you happen to live near one, then regardless of how much money you have available it is always highly recommended. Somewhat similar concerns about multiple stores though.

As for types, others have said already - beans, chicken, rice, etc. Much of that could change in the future as a result of tariffs.