Cost estimation helps build confidence in the feasibility of the development of novel manufacturing processes. This paper focuses on the exploration of the cost estimation for novel manufacturing processes for decision support. One of the aspects of estimation is building credibility around the analysis, especially, in the early stages of planning. Cost estimating guidelines provide a good overview of the cost estimation steps but there is a requirement for guidelines for cost estimation model development. Through building on an understanding of the cost estimation principles, as well as cost estimation modelling, a high-level generic approach for process cost estimation is proposed. Further, a demonstration of a cost estimation modelling approach used for composites manufacturing in the automotive sector is provided, outlining the steps in cost estimation model development.