When we have craft shows, there is always a table or two of someone with their homemade spread. I believe they just rent a space like a regular crafter.
Also--local farms that prepare honey or baked goods--often sell to produce market stores.
You just have to make sure you are following your state laws for food prep.
I know some underground bakers--but legally, in Florida--they shouldn't be selling cakes b/c they do not have a commercial kitchen. But they do it by word of mouth. I know 2 locally and my mom will also sell wedding cakes underground.
I have no idea if the requirement is the same for something such as a food spread, though in our state.