This is "Okigushuri"(putting medicine?).
The peddler of the medicine sometimes visits each home. And, he leaves this box set of the medicines.
When he visits next time, he receives prices only of the medicines used in the box set from the user. And, he replenishes the shortfall. It looks like the method of the credit card a little. This business method extended to the Japanese whole country in the early Edo period (the 17th end of century). Toyama that was the production ground of medicines was the center of this unique system.