Functional 3D Prototype With Springs

I need a fully-working 3D printed prototype built primarily for functionality testing. At its core the design relies on a compression-spring mechanism, so the hard parts must be strong enough to take repeated load cycles and keep tight tolerances around the spring pocket and guides... (Budget: $30 - $250 USD, Jobs: 3D CAD, 3D Design, 3D Modelling, 3D Printing, 3D Rendering, CAD/CAM, Local Job, Mechanical Engineering)