Eric and I tore down our old garage and recycled most of the materials by bringing them to the proper facilities. Things learned: shingles and asphalt are heavy. Also, budget double the amount of time you originally plan for. I should know that already.
We had the garage built by JML Roofing & Renovations (pad, walls, roof, shingles, stucco, windows installed) and did the electrical and walls ourselves. We dug a trench to our house so we power the garage with enough electricity for both of my kilns. Fun times!