Know anyone who goes camping and lacks this basic of (car?) camping equipment?  Even if your sewing skills are only very rudimentary, these stools are easy to make…  Use stiff canvas to make a triangle for the seat. Sew on 3 triangular "pockets" to the corners (sew the 2 outer edges, leaving the inner edge - which you've turned under - open; use double seams for strength!). Into the pockets you’ll put 3 sections of thick doweling legs (sand the cut edges)... and lash the doweling in the centers. (You can staple or tack the seat to the legs, though this isn’t necessary - it would be good to at least create a tether between the seat and the legs so the pieces don’t get separated from each other.)