School-based health services (SBHS) have been implemented in rural primary schools to improve students' health and reduce absenteeism. However, their long-term economic impact and accessibility remain underexplored. A mixed-methods approach combining surveys and focus groups was employed to assess student attendance, health service utilization, and cost-effectiveness. Data from 100 randomly selected schools were analysed. There was a significant increase (p < 0.05) in school days attended by students who received SBHS compared to those without, indicating improved access and usage of services. SBHS led to substantial cost savings for families and the government, with an estimated $10 per student per year reduction in healthcare costs. Further studies should be conducted to assess scalability and sustainability of SBHS models. Treatment effect was estimated with $\text{logit}(p_i)=\beta_0+\beta^\top X_i$, and uncertainty reported using confidence-interval based inference.