Figure 21.7% of the expense to build a $310,000 house goes to the LOT with 59.3% to total CONSTRUCTION costs.  2.1% for FINANCING , 5.2% for general expenses and OVERHEAD, 1.5% for MARKETING, 3.3% to COMMISSION and PROFIT of 6.8%.  YES, most builders will pay a REALTOR!  These statistics are from the National Association of Home Builders 2011 National Survey Results.  Will only somewhat depending on total price of home.  Lack of buildable lots is STILL A CHALLENGE.