In the medieval times, we had "iron mongers", blacksmiths, or those who dealt with blacksmiths, to commercially distribute plough and nail and, if the occasion arised, weaponry. The term even continued until the present day in England. In America, we have the hardware store, a term who's services could be quite broad. It can include everything from appliances to planks of wood and floor tiles to greenery, as well as services like repairing lawn mowers, filling propane tanks, and copying keys. Some rural areas even sell seeds and feed for livestock. This latter aspect, as well as the all-purpose versatility, allowed them to be the most widespread permanent, "specialized" outfit (as opposed to general stores or market stalls) after the collapse of society.
As it was the brick and mortal store was on its way out. But with material, almost post-scarcity commerce dissipating, the most steady(if somewhat low return) route for enterprising merchants were those who provided the raw materials for a more do-it-yourself-culture, as well as providing handyman services for those who could not do it themselves. Wood and axes and many seeds were what people needed most in a more rustic, agrarian world.
The Hardware Store of Medieval America in some ways resembles a Bass Pro Shop than a Home Depot, but most closely harkens to the hardware stores of small town America. While a place to get a piece of metal repaired (generally cheaper than outright replacing) or emergency firewood, they are also something of a social center--like the malls of modern America, or maybe pubs. (In fact, because inns and taverns are not quite as widespread as films and TV about medieval settings indicate) They're sort of a off-town square town square, descending from Americans trying what customs they can from a new, harsher world that has denied them.
