The frame is the wooden beams that form the skeleton of a house. This is a surprisingly expensive part of building a house, just because of the large amount of materials and skilled labor needed to complete it. Framing may not be as expensive as foundations or soil, but it's usually more expensive than the other items on this list. Taking shortcuts in the structure of your house isn't exactly wise.
Houses are built with wider spaces between beams than they used to be, but even that doesn't mean a lot of savings. Some people build houses with shipping containers, which can reduce the cost of the structure. However, this is usually not suitable for large houses and has its own disadvantages, such as inflexibility and quality issues.
