Most common goods in those days were perishables. Shelves would contain, "canned goods", boxed fancy soap, cans of oil for lamps, bolts of fabric and bottles of tonic, home remedies and whiskey. There may be a rack with a couple of pistols and rifles on display with ammunition kept either beneith the rack, or under the counter. A display case on the counter may contain fancy things like men's razors, lady's hairbrush, and hand mirrors. The counter would hold glass jars of hard candy for the children and adults alike. That would be best placed next to the cash register, so the shop keep could keep an eye on little hands. The floor would have sacks and small casks containing flour, cornmeal and feed-oats. And don't forget the hand-tools. That's all I can think of right now. Hope it helps.