$100,000 is not enough to build a Custom-tier casita or detached studio in Las Vegas. At the Custom tier ($550 to $850 per square foot), a $100,000 budget covers less than 200 square feet — smaller than the smallest usable casita format. Custom-tier detached studios typically start at approximately $210,000 for a 300 square foot layout with a kitchenette and single bathroom. Homeowners with a $100,000 budget who want a functional secondary living space are usually a better fit for a production-tier ADU builder than a Custom-tier design-build firm like Kingdom & Co.