When I worked at a lumber yard, contractors, co-workers, and manager always said "the basement is the cheapest room to build." And if done as Airtime advises they are dry and warm (or cool) as preferred.
Basements would be nice ,, but the areas I'm looking to build in are mostly flat ,, so the basement idea isn't really feasible at the moment.
SB re: post #22. SB I don't understand why flat terrain inhibits basements. Unless water table or bedrock is too high. Please explain.
It's far cheaper to form and pour flat work than to form 2 sides, that's the principal reason. Very effective, done right. Hauled out of the fab yard on flatbeds and erected in place with a suitable hoist, one pick per slab. Poured in place takes two picks at least for the two sided forms, PLUS the rebar lifts PLUS there's the concrete pump.