The manufacturing sector is undergoing a significant transformation driven by the demand for personalised products, challenging manufacturers to provide precise quotations while maintaining cost control and profitability. Product Configuration Systems (PCS) play a pivotal role in supporting product configurations, facing challenges such as data integration, cost calculation relevance, and the need for a knowledge expression framework. This study significantly contributes by delineating an object-oriented ontology framework tailored for configurable product families within PCS. It incorporates comprehensive domain information models for MBOM, inventory, purchase, manufacturing, and sales and distribution. Additionally, the study proposes a domain information model-based cost estimation, integrating actual values from existing Enterprise Resource Planning (ERP) systems for various cost aspects. Design patterns for transforming domain information models into system implementations are introduced, covering both data and business operation layers. Practical application and feasibility are demonstrated through a detailed case study, emphasising the method's practicality. The proposed approach empowers manufacturers to derive accurate product cost estimates, supporting well-informed business decisions. Future research directions involve refining product model configurations, expanding support for diverse product types, and integrating additional digital technologies for an enhanced user experience. Further exploration of labour, equipment, and engineering design expenses aims to enhance cost estimation accuracy.