Executive Homes Cost More. A prefabricated home costing $259,000 in materials only, will end up costing approximately $581,000 to $854,000 with the land costs, building costs and additional expenditures.This home will have an average of 6,200 square feet with two floors, a full basement, four bedrooms and three full baths. prefabricated home costing $259,000 in materials only, will end up costing approximately $581,000 to $854,000 with the land costs, building costs and additional expenditures.