The price is primarily driven by the base material (FR-4 is standard), the number of layers (typically 2 to 4 layers for smart detectors), and the copper thickness (1oz is common). For high-reliability smoke detectors, ensure the PCB uses High-TG (Glass Transition Temperature) materials to maintain structural integrity during fire-related heat stress. Additionally, the integration of SMT (Surface Mount Technology) for components like the microcontroller and infrared sensors significantly impacts the final PCBA (Printed Circuit Board Assembly) cost.