Some tips for building an affordable home are building a second story, using simple shapes, centralizing the plumbing and building a simple roof. It's less expensive to build a house that is taller rather than wider, because the most expensive parts of a house are the foundation and the roof.
A wider house is more expensive because it requires a larger foundation than a tall one. Adding a second story doubles the overall square footage of the house without the owner paying extra for a larger foundation.
Just as the foundation of the house takes up a large portion of the overall construction budget, the roof of the house takes up a considerable amount as well. Therefore, complex roof lines should be avoided, not only because they are more difficult, and therefore expensive, to build, but also because they have a higher chance of leaking.
It is more affordable to build a house using simple shapes, such as squares and rectangles, than irregular ones. It takes more planning and material to build a house using complex shapes, which increases the overall construction costs.
Another feature of an affordable house is centralized plumbing, in which the rooms that require plumbing are placed close to one another. This eliminates the cost of running a large network of plumbing throughout the house, which can be expensive.