First, off are you talking tube steel or red iron? Big difference in cost and you need to determine your need. Mine was just for a shop and tube steel was just fine. A 24x36 with two ten foot doors and a single walk door cost me $7500 in 2016. It was built on a slab that cost me $3500.

I just priced the same thing again on Max Steel Buildings and the price is $13,470. And I know concrete has gone up. Hope that helps some