I'm still in very preliminary stages now, as our house goes on the market next week.

i'd be more concerned with your house selling.

as for a steel building call around. the basic one where doors open on the end are low priced. once you vary the price goes up. our garage (24x30)
is listed for X dollars. once we changed where we wanted the doors 9how many) window, entry door the price went ^up!.
a concrete pad and apron are a must.

regarding wood vs. steel. my "garage" is listed on th etax rols as an out building. as it is not frame construction.

we had it spray foam insulated roof included. when it's -15 outside its 33 inside w/out heat.