Dollar stores do not sell food.
They sell junk and say it is food.
We have a Dollar General, and several Indian-run “dollar stores”; I don’t view them as competitors they just seem to sell very different items. The dollar stores have a lot of cheap Asian goods (kitchen utensils and such), the Dollar General has a lot of food (mainly canned/boxed), a small refrigerated/frozen section, greeting cards, medicine, and clothing. I see little of what Dollar General sells in the dollar stores.