20 Heller Sarmingstein

Sarmingstein is a tiny market commune on the Danube in Upper Austria, and this 20 Heller emergency note is exactly what it looks like: a local community scrambling to plug a small-change shortage during World War One, when coins vanished from circulation across Austria-Hungary almost overnight. These Notgeld issues were printed by whatever press was available locally — in this case J. M. Hiebl's print shop in nearby Grein, a few kilometers upriver.

The official stamp is the only security feature, which tells you everything about the trust model: this note worked because the issuing commune was known to every person who handled it.