Salt was not expensive for people living near the coast. It got very expensive for people not living near the coast, where ships don’t help much with transportation. It’s heavier than water by volume, because it’s a rock.

I was adding to your comment, because you skipped over the shipping costs, which made up the majority of the price for people not lucky enough to live near salt production.

It’s like mangoes today. If you live where they grow, they’re cheap as fuck. If you don’t, they’re expensive, but not impossible for most people to purchase.