Not that much actually. Much cheaper than traditional wooden construction. If you’re looking for a cheap metal carport, for one small car, you might get away for less than $2k. In the other direction, the sky is the limit. Large commercial warehouse construction can easily get into the 100’s of thousands. An industrial chicken coop, commercial greenhouse or large multi-bay garage workshop would certainly fall into that category as well. A small residential garage or barn might be around $10-$20k while larger structures would be more towards the $30-$40-$50k range.