Cheapest possible steel structure?

Hello,

I am currently considering building a 200sqm house or hall in a completely different way. First, only the land will be purchased, then a two-story steel structure in the shape of a cube will be designed and built, which is stable enough that nothing can fall over. It should have no walls and no concrete floor on the first floor. How much does that cost? The price has to be as low as possible.

I want to be able to freely express my creativity on this steel structure. Initially, only a tarpaulin will be wrapped around it to protect against cold, wind, and rust. Later, stone walls, wooden boards, or glass walls for floors and walls will gradually be attached. There should be no construction time, but it should simply be built step by step depending on money and luck on Ebay.

So purely a cost question for just steel beams. And what do the steel beams look like? How thick will they need to be?

That won't work like this ...

That doesn't work ...

because it is technically not possible?

First of all, it is not allowed, I would say.

please reasonable answers. not whether something is allowed or not. purely technical questions. what people say about it doesn't matter to me. it's only about the functionality. then a place will be chosen where it is allowed.

Yes, probably in Bulgaria... Why are the questions about which material the architect wants?