What kind of materials would you want the test version to be made from and where are you located? Be aware that if you need something machined out of metal, this can be expensive. If you need special plastic injection moldings--which require very expensive molds--this can be VERY expensive.
My general policy is to answer every question on the board, which is what it's here for. For this one, when you advise the above general info, I may make an exception. But part of an invention is figuring out how to make it and cheaply enough to translate into marketable products.