3D Model Repair for Printing

I already have the 3D model designed; what I need now is a precise mesh-repair pass so the file can go straight to the printer with zero fuss. Your task is to hunt down every hole, non-manifold edge, flipped normal, and other print-killing flaw, then return a perfectly watertight, manifold solid... (Budget: $10 - $30 USD, Jobs: 3D Animation, 3D CAD, 3D Design, 3D File Scaling, Slicing & Print Preparation, 3D Modelling, 3D Post Processing, 3D Print Design, 3D Printing, 3D Rendering, Solidworks)