How it works
Population sets the base scale. Prosperity (×0.5 / ×1 / ×2) and magic level (×0.5 / ×1 / ×2) both multiply the gold-piece purchase limit; prosperity also scales available cash.
Trade demographics use rough historical fractions of medieval populations: 60% farmers, 1.2% innkeepers, 0.6% blacksmiths, 4% guards. Prosperity scales merchants; magic level scales healers and alchemists.
Use as a starting point for session prep; tweak counts manually for plot-specific NPCs.