If you have cinder blocks laying around, and won't need them for a permanent building
project, I would just use those to make your temporary
rocket stove. It will be very quick and easy. They will not last a long time, but
should work at least for a season of burning scrap wood.
Old soft bricks would be better if you have them or can get them free or cheap. You can make mortar from clayey mud to stabilize a temporary brick rocket. It will not glue the bricks together, but will seal gaps and keep things steady.
If you have nice clayey subsoil, you can most assuredly make a
rocket stove from that. A scrap wood inner form that you can burn out will work well, and mixing some
straw into the clay will reinforce it. As long as it is isolated from damp ground (on rocks or concrete) and protected from rain, it will bake on the inside and start to become fired.