Medium-Detail STL Model Creation

I need a printable STL file produced from my concept. A medium level of detail is ideal—clean surfaces, sound wall thickness, and a mesh that will slice happily at standard 0.2 mm layers without ballooning the file size... (Budget: $10 - $30 USD, Jobs: 3D CAD, 3D Design, 3D Modelling, 3D Print Design, 3D Rendering, AutoCAD, Blender, CAD/CAM, Fusion 360, Solidworks)