I'm good at this, I made two (three if you count the time one was dismantled and moved). Any way one was 10 by 10 and the other was 8 by 12, both under $400 each.
We used economy studs (rough 2 by 4s) and chip broad, the miss ordered shingles, and miss mix stain. Long as you stain chip board really well, and keep organic material away from the sides, it will last until you can get siding. You some times can get extra siding, even constructing business sometimes have part bundles of shingles and stuff they'll give you.