Not sure as to why you would ask this on a website.
Typically the "camp stores" I have seen carry small amounts of food/grocery items like bread, buns, canned goods, some frozen items, ice, drinks in a food section.
They have some "camping" items like extension cords, sewer connections, water hoses, minor camper repair items (bulbs, fuses, adapters ect)..
Tourist type stuff like T shirts, knick knacks, post cards, gift items and so on.
They typically are not afraid to charge for those items but keep in mind if you have it and someone needs it it is often worth the price just so you don't have to break camp or drive a ways out of the way to find it.
Personally, your food items would be where you need to find a LOCAL FOOD "wholesaler", ask some of your local grocery stores to see if you could get a contact name of their supplier. Keep in mind, you may not have enough "volume" in sales to make it worthwhile for large wholesale chains.
Your other stuff, not sure on that, you could check with a few local RV dealers and see if you can strike up a deal that they supply some basic inventory on consignment, you supply some space and make a percentage profit of the sale price.. Without you buying and holding inventory..
Tshirt/knicknack stuff, check with your local mall/shopping center, you might be able to find a small independent vendor that may be willing to set up a small kisosk in your store to see if you have enough sales to make it worth while.. You would get a small percentage of the sales but this way you are not buying and holding inventory.
