Years ago I needed a cheap, small, temporary storage building. I bought a couple (8) sheets of 4 x 8 plywood a handful of lag bolts, a set of hinges for the door, some pre-cut 2 x 4’s, and a couple more 2 x 4’s for framing.
Framed up the floor, nailed and glued one sheet of plywood to it.
Cut one sheet down to 7ft on the one side and angled down to 6ft on the other. Bolted two frames made from the pre-cuts as framing set sideways on the back piece and framing for the front using the leftover piece of plywood from the rear as the top. This gave me a solid back wall and the front wall with a 6ft tall by 4ft wide doorway.
I then hung a sheet and a half of plywood for the short side and a sheet and 2/3rds for the back. Cut my last sheet at 6ft and used the remaining plywood to make a few gussets where I thought they’d benefit.
The roof was a final sheet of plywood with a 1 x 6 to cover the gap at the top.
My further plan was to build a second one and butt it to the back of the first one to give me a bigger building later. I probably had less than $100 dollars in the whole thing. Set it up against the mobile home I was living in.
I sold the place and told the new owner I’d take it down and take it with me but he wanted it so I just left it there for him. A couple of years later he had added roofing to it and painted it. Otherwise, it looked the same.
It occurs to me this nice ‘half shell’ would be handy as a storage building most anywhere and form the basis of a nice ‘tiny home’ dwelling, office, or shop.
Further thought and some investigation made me think of using two or three 2 liter soda bottles sealed into holes in the roof for daytime lighting (cheap and no glass to break). A ring of cheap solar lights let through the roof surrounding those bottles might add some extra nighttime lighting.