The builder offers their plans built with a base price on a standard sized lot. They frequently have the lot price included in the base price. If the builder has several lots available on which to build a plan, some may be more desirable than others by virtue of exposure, size or location. Those more desirable lots will have a "premium" to purchase them. That can be from a few hundred dollars to over several hundred thousand dollars for a lot on a prime golf course or lake. The same applies to selection of a floor in a condominium; the higher the floor or the better the view or exposure, the higher the premium. The penthouse unit may be identical to one on the first floor, but will be much more expensive.