Rain-Proof Smartphone Holder Design

I need a practical, waterproof phone holder that will keep a medium-sized smartphone (roughly 5–6 inches) fully protected during heavy rain. The goal is to allow the user to operate the screen, see notifications... (Budget: $15 - $25 USD, Jobs: 3D CAD, 3D Modelling, 3D Printing, CAD/CAM, Concept Design, Mechanical Engineering, Product Design, Solidworks)