I thought about the height and you can get a high box version which is 9' I believe. Ive seen prices for a 20' at $800-1000 delivered so its comparable to a conventional garage, although a small one. Yes a lot of cutting and welding but this just an idea for now. I wouldnt have to pour a slab just a footer as the floors are usually some kind of hardwood. Buff and shine and my garage would have a killer floor
I also think it would be less labor intensive as they would deliver to your site just put them close enough together or just ram it together 86 Ranger. Walls,floor ceiling,doors are in already
and I would take my time cutting out the side and filling the gaps. I think it can be done for under 3k with the roof being made from sawmill lumber and you would have a solid floor for storage above the garage, they stack these things 20 high on some ships