Most products, however, use multiple sources. When a product uses multiple sources, one of those sources may even agree to put all of the pieces together for you and possibly even warehouse inventory. The brand name selling a product may have little to do with who's making it. Manufacturing sources tend to specialize. Zinc, plastic and steel represent three different technologies and three or more different manufacturers.
Specialization can go quite deep.
Doing your homework to find out how much it would cost to make a product requires communicating with each source. Unless you are an engineer or an industrial designer, you will want to hire someone to help you. IDSA.org is a good way to find a design firm in your local area. Before disclosing your idea to engineers, industrial designers and contract manufacturers, it is good business practice to ask them to sign a non-disclosure agreement. Part of that agreement should specify that any idea they have while working on your idea becomes your property.