My wife and I have been looking for a house that we love for some time now. We just do not want to settle. A recent idea is that we can build a house that we would love. We plan on having some kids so to start we would only need 2 bedrooms and 1.5 bath.

We know a lot of people in the construction trade that can help us out for little to no cost. One question I do have is; is it possible to just attach metal siding to the frame of the house then use a spay foam insulation and drywall over the insulation to save on costs?

We really want to try to keep costs around $100k in the WNY area and are looking at ways to cut costs. Any help would be... helpful. Thank you!

What brand? What thickness? What tensile strength? What kind of roof bearing it's weight down the walls, that will have lost a lot of structural integrity by doing this? What climate are you in? Any metal siding that isn't stainless (which you can't afford) will be steel, and even with a baked on powder coat, it will suffer dings and scrapes and eventually rust. Do you have a building inspector? It might not even pass without sheathing under it, which adds to the integrity. You have your work cut out for you. The metal siding manufacturers will have all those answers.

Any product online has specs that go into deep detail, but usually from the manufacturer, not the stores or online.

It would take all day to discuss all aspects of the materials that go into a house. Mostly you really do get what you pay for. Cheap materials cost more over 20-30 years.
Even foam insulation vs fiberglass batts is a topic to price out, including 2 x 4 vs 2 x 6 walls.

Make a list of all major materials. Price them, study blogs about their use and any reviews, and think twice about cutting corners.

Two of the biggest decisions you will make are slab vs basement, and type of heating.

Armstrong Steel Buildings

https://www.pinterest.com/explore/metal-building-homes/

Metal Building Homes Guide

Kodiak Steel Homes | Models and Pricing

There has got to be a million hits if you Google "metal homes" and "metal home costs"