Making a prototype

It depends on the product. You can 3D print it for cheap if you know how to 3D model and how to optimize the design for the production method. If you don't, you can hire a company to prototype it but it ain't cheap. Really just depends on what your are trying to do. The more complicated it is to produce 1x widget in a production setting, the more $$$ the prototype is going to be.

It would be a plastic mold prototype. Nothing fancy