I picked up a very light weight sturdy "Stanley" step/stool for €15. Granted it doesnt have a back on it...........so you wouldnt sit for hours on it observing..........but it would do very nicely for resting your bones on while observing. It has a big(ish) storage compartment underneath the seat (torch,EP's,books etc).
It stands about 8-10 inch high and has a fold away handle also.
I just saw it and thought "Oh that might come in handy" because the spot in my garden where i do most of my observing is in a corner just outside the back door. Its a small corner cuz of the flower bed and when i have my scope and wheelchair there.....................there is NO room to move.
I just thought i'd mention it because it really is a light weight option. I think it weighs about a half a kilo......................
P.S.~~~i'm a guy of generous proportions and it holds my weigh no problems. Nice size seat on it too.................no over spill.
Paul C
My next scope is going to be a Vixen VMC200L Catadioptric OTA