First, contact local builders to find out a rough estimate of construction costs per square foot. To this amount, you need to add the cost of your lot, builder profit, septic systems, wells, permit fees, etc. This will give you a good idea of whether or not the house design is within your budget. However, there is no substitute for actually sitting down with your builder with a full set of house plans and establishing budgets for all aspects of the home. This includes lighting, carpet, cabinets, plumbing fixtures, etc.