There are three main options for buying a new construction home.
Option one: Buy a lot of land and then hire an independent builder to construct a completely custom home.
Option two: Buy a "builder house," or a new, move-in ready home built by a builder company on a lot of land, not in a new construction neighborhood.
Option three: Buy a spec home in a new construction neighborhood. In this scenario, you will choose from a few different predetermined home styles to be built in a neighborhood with mostly new homes.
The price of land is almost never a factor when purchasing a new construction home, unless you are buying the land and hiring the builder, as in scenario one.