I still shop at my closest Walmart..price wise, their brand name groceries can only be matched by the discount stores that carry "store brands" and don't even furnish bags.
I goofed at buying ammo a couple months back, I bought a couple 50 round boxes of WW .22 mag..got home and discovered I had solids instead of the HPs I really wanted, as I almost never use solids.
I did recall the sign that said flat "no returns on ammo" ...and just "swallowed" my mistake, figuring the boxes were clearly labeled "solids".
I guess if I were the manager, I would have tried to accomodate you..but there is something about ammo..a lot of gun shops have the same "no returns on ammo"
sign posted.
In any case, If I refused to buy groceries at a Walmart Supercenter..getting brand names at a local super market would run, I estimate 20% to 30% more $$.
In my case, I would just be "cutting my nose off, to spite my face"..