The first substantial difference in building versus buying an existing dwelling is the additional time and cost of planning, design, and permits costs. You are also likely to face more scrutiny from neighbors and the local government building/zoning department if you build new versus a remodel or addition. Many of my contractor friends tell me that remodeling and adding to an existing house with good bones is a great alternative to building new. Another benefit to a remodel is you will have a better selection of fixer properties to choose from versus finding developable raw land.
Second, the cost per square foot to build a home varies based on several factors. One, building materials are available in varying grades and prices. Two, the type of home you build is a major factor. A two story home will have a smaller footing, thus it will cost less per square foot. The cost per square foot can range between $150 to over $200 or more to build new.
If you wish to speak with a contractor and get more specific answers, send me an e-mail and I will gladly forward it to some contractors for more detailed answers. Jeero@GlencrestTeam.com.