You're talking about building some kind of enclosure box? Sure, that's a pretty common use of 3D printing, although there certainly are other ways of doing that which might be quicker, stronger, or more efficient (you can buy pre-made plastic enclosures in a wide variety of shapes and sizes). Yes, it's easy enough to print a model in parts which then can be screwed together. As to what machine to use, it depends on how big these things need to be, and what material is to be used. Cheap printers tend to have small part volumes; to get a larger machine, you'll generally have to spend more. And for some materials, you need a heated bed, and/or a heated chamber for good results.