What was the operation of the zen. Johnson General Merchandise Store?

From the text:

The formal name of the Store was the Wm. Johnson General Merchandise Store. Customers could find food staples, a good variety of colored thread, mash for hogs, corn for chickens, coal oil for lamps, light bulbs for the wealthy, shoestrings, hair dressing, balloons, and flower seeds. Anything not visible had only to be ordered. Until we became familiar enough to belong to the Store and it to us, we were locked up in a Fun House of Things where the attendant had gone home for life.