I often have trouble trying to figure out the kind of store they would have in small fantasy towns. If you read Urban Development, you’ll see that any village of 500 or more people should have two or more stores. I always assume the first two are the dry goods store and the grocery. But what do they sell at the dry goods store?
So it hit me how easy this is. Do you have a farm and ranch store near you? There’s a bunch of these but by far the best is Tractor Supply Company. Take a walk through there and the ideas should just pour out. Now obviously, you have to convert modern to fantasy. Non-power tools are likely exactly the same, though no wrenches or screw drivers. Any vehicles or trailers need to be broken down to wagons and carts and the number needs to be reasonable for the population (probably only one cart and one wagon). Clothing probably doesn’t exist, but might be replaced with fabrics. The again - some clothing might work: belts, gloves, lederhosen, maybe even a jacket.
Forget the power tools, but maybe not their function, such as an auger instead of a power drill. Don’t forget the animal feeds, but would they be in bags or piles? Truck boxes might be chests; tarps might be canvas instead of plastic. Ropes, chains, fertilizers, pesticides, even wheel lubricants should be there made from era appropriate materials.
What about food? Well the jerkies seem a good fit, maybe even some of the snacks like pretzels. The food probably depends on what the grocery store stocks, but maybe it’s rations at the dry goods store and flour and other foods at the grocery. If your world has beer in bottles, this might fit too. Just like TSC, the dry goods store has no refrigeration.
TSC works well because they have a very broad selection of stuff but not as deep a selection as you might find at a hardware store. Think of a big box hardware store - you would get lost in the hammer aisle. Even still - you need to lower the inventory; small town shop keepers cannot afford to carry inventory.
Why does it matter? Because personally I’m sick of not knowing what’s for sale. PCs stroll into town and want horses, saddles and spurs. Not at this country store. But if they need a weapon, how about an axe or a hammer? Knowing, or at least having a pretty good idea, really makes it easier and better.