Multi-Purpose Pen

So the pen that you see in the given attachment has been designed by me. The slot on the upper side of the pen is designed in such a way that it can hold a smartphone of 7.55mm to 8mm and the rubber nob in the upper most type can be used to operate it's touch panel. Any suggestions would be welcomed and I would also like to know how much would it cost to make a simple 3D model of this pen. Thankyou.