Rapidobe is an extremely fast and cheap method of building. It involves putting posts into the ground, attaching a U-shaped bag to them and filling it with any earth available.
Building from scratch is a vast undertaking and can be very daunting. However, take it one step at a time, living in each room as you go. Before you know it, you will have the house you were dreaming of.
If you have bought land with nothing on it, it's a great idea to build yourself a small starter cabin that has nothing to do with your final home design. You can always strip it down and use the materials later, or keep it as a shed.
Wood is a softer material than metal and can handle a lot more hand tools, which are generally cheaper.
Metal is one of those materials that requires specialized tools, mostly electrical. Some are more of a luxury than a necessity, but others are fundamental.