Aluminum
warm,lightweight,cheap.
Steel
aluminum
The most lightweight is aluminium but they are seldom the most expensive.
Aluminium is cheap, lightweight, strong, highly malleable and corrosion resistive. Hence it has all the qualities required to make a utensil out of it.
Alloys of aluminum are used for making ladders because they are lightweight, strong, and corrosion-resistant. This makes them ideal for applications where a portable, durable, and low-maintenance material is needed, such as in the construction of ladders.
Because it is cheap and lightweight.
cause its cheap, easy to mold, and lightweight.
All of those qualities are relative. Aluminum is a good start. For formed sheet metal, type 5052-H32 is pretty common.
It's light enough, cheap enough, strong enough and easy enough to work with.
No but it is strong.
It is cheap, it is strong, it is reliable, it is versatile and it is simple and easy to use. In short, there is the perfect building material.