Soil types vary from land to land. It can be loamy, sandy, or clay soil. When purchasing Land which you intend to build on, it is vital you seek out soil that is coarse enough and suitable for you to build on.
The best cost-effective land to purchase is dry land with loamy soil, which is easier to build on directly.
Generally, you want to avoid areas with swampy topography, as they incur more cost to be dredged up and sand-filled before laying of the foundation before building can start.