Stamp vending machines in the United Kingdom
A stamp vending machine (SVM) is a mechanical, electrical or electro-mechanical device which can be used to automatically vend postage stamps to users in exchange for a pre-determined amount of money, normally in coin. Most SVMs were positioned in public places to provide a useful service to customers when other sources of postage stamps, such as Post Offices were closed.
Source: Wikipedia — Stamp vending machines in the United Kingdom (CC BY-SA 4.0)