Sustainable access to Research Infrastructures (RIs) is essential for fostering scientific innovation and collaboration. This document examines financial frameworks and cost models for access to distributed atmospheric RIs, emphasizing the balance between affordability and sustainability. The study outlines a diversified funding strategy combining diverse funding sources. A comprehensive unit cost analysis allows to estimate the required resources needed for ensuring broad access. The findings support the development of equitable, transparent pricing schemes tailored to user categories and service types that ensure long-term financial viability while preserving accessibility and research excellence.