The key to controlling your modular building costs is to determine what portions of the structure will be factory installed and what will be site installed.  Using standard products installed at the factory will assist in keeping your  overall construction costs down.  Site installed interior and exterior finishes typically cost much more per-square-foot than factory-installed finishes.  Low-cost modular buildings might have factory installed aluminum siding while high end modular buildings might have a site installed brick veneer.  Structurally, they could be identical buildings, but look completely different because of the exterior veneer.  The ultimate decision between using a factory finish or a site applied veneer hinges upon the balance between your needs, desires and cost objectives. 

It is essential that your material selection be made based upon your project objectives.  Material quality standards must be weighed against the construction funds available.  This may, at times, result in building less square footage in order to maintain the desired level of material quality.  The standards of high quality will affect material selections, systems choices and design aesthetics.  Material quality will also have a significant impact on the future resale value of your modular building.