Some cost a bit, some almost nothing. Note that the price of steel siding and also roofing, although common, are not cheap. I found that for about $200 dollars more I could have vinyl siding over OSB and for about the same, a shingled roof, again over OSB. The 8 foot over-hangs on both sides added about $1 to $2K total and the 12' soffits (eaves) somewhere around $500. Pictures follow: