medicine left by a salesman, paid for when used
Refers to a traditional system where a pharmaceutical salesperson leaves a box of common medicines at a household or business, and the customer pays only for what they consume. The salesperson periodically returns to restock and collect payment.
At my grandmother's house in the countryside, there is still a box of medicine left by a salesman.
The salesman for the medicine-on-consignment system comes regularly to restock and collect payment.
Compound of 配置 (placement, arrangement) and 薬 (medicine), literally 'placed medicine'.