With the global financial crisis happened, companies and investors pay more attention to development expense. Development costs mainly include design cost at the design stage. We analyze the design process and extract many design factors in order to estimate design cost at the conceptual and embodiment design stage. A number of process-based design features that impact the design cost are considered. These design factors include: 1) the number of performances and constraints, 2) sub-functions level and relationships, and 3) solutions at the conceptual design stage. At the embodiment of the design stage the design factors include: 1) the number of parts and their relationships, 2) the types of materials, 3) load resources, and 4) the number and types of tolerances. We use relative cost to estimate design cost by comparing the number of design factors among designs. To demonstrate the relative design cost estimation in practice, Kodak single-use cameras are used as example products. Use of these methods proves beneficial in estimate design cost in the design process.