UK: I don't know if it's produced domestically, but pasta is dirt cheap. Own brand spaghetti can be under 60p a kilo. Tinned tomatoes are also cheap, so there you go - dinner.

Potatoes and brown onions are fairly cheap, ditto carrots.

Eggs, of course. £2.70 ($3.50) a dozen, medium free range.

The US is too big for a single answer, but here in Florida bananas are cheap, but potatoes and apples are expensive. Sweet potatoes are often cheap though.

I grow some stuff here, that's not free but is cheap for sure. Okra, jalapeno peppers, watermelon, purple sweet potatoes, basil in the summer. Greens, lettuces, broccoli, cauliflower, radishes, fennel, cilantro in the winter. Mint all year. Have citrus trees and a fig, all dwarf trees so not a huge harvest but an easy one.

I think wine and most booze will get very expensive, grains, so flour, pasta, bagels. Good cheese. A lot of produce since it comes from Mexico and South America and our supreme leader here seems determined to piss them off. Milk will probably stay around the same, maybe domestic cheese. I would logically have said eggs, but apparently not.

Dollar tree sells staples at a dollar 25

Swingline are pretty affordable ᕕ( ᐛ )ᕗ

The cross-section between high volume and easy to make

• Vegan replacement products? Easier to make than animals, but low volume so it's more expensive than it needs to be (and often in a higher tax bracket, classified as candy or whatever)
• Eggs? Needs healthy animals
• Bananas are clones of each other. Might become an issue at some point, might not. Apples, too, but there's many more variants
• Maize, tomatoes, potatoes? Grown by the bazillion, cheap, afaik needn't be clones of each other to get (something close enough to) the desired product
• Rice? The pre-boiled stuff is afaik around the same price as the raw product, that's how large the volumes are

There is only relatively expensive.
Literally everything has gone up with every excuse possible.
Covid, some ship that blocked the Suez canal?!, war in ukraine, not enough rain, too much rain.
Prices never go down after.

Lotta cranberry bogs here, and tomatoes.

I live in the US and honestly, I don't think anything will remain inexpensive. Even stuff that is produced domestically will go up in price because a) the value of the dollar will contine to decrease and b) if companies can get away with increasing prices while pointing to some external excuse, they will.

US, specifically southeast Michigan: Ramen, bread, and spaghetti, though as other commenters have said everything has gone up, so even these.

Clay, I can walk 100 meters and dig it out of the ground for free.

Water, it rains about 200 days a year.

Canada. Lentils, potatoes , rice.

Take all this for a grain of salt I'm at work and didn't have time to verify these numbers. I got them from AI, but the order makes sense. They also don't include secondary and tertiary effects. E.g. what tariffs on China will do to goods imported from Japan.

In the United States, corn, soybeans, and wheat are projected to go up a maximum of 5%. We produce upwards of 40% of those goods, so they will be the ones which will impact other countries the most. Meat will go up more. We domestically produce 12-15% of the world supply of pork and beef. Produce is going to be hit badly. Up to 40%.

Gasoline and other fossil fuels is difficult to determine. We import a lot from other countries, directly from Canada, but companies based out of the United States have off shore drilling rights in locations around the world. Increased costs of fossil fuels, may have increased incentive for renewables and nuclear, but oil companies have historically passed those losses on to consumers.