Kits just contain the same materials you would use if building from scratch: 2x4s or 6s, rafters or trusses, sheathing, shingles, siding of your choice, window(s), door(s) - they've already done the takeoff. You have to provide the foundation.
There's a big gap in what different people consider ok to live in. I assume in MO you experience winter, so you better have them takeoff a finished, insulated interior.
So many questions to be left unanswered.