An anti-recommendation - I got a mini stair-climber machine once that was just the foot part, no handles or display or anything, so it was about 8" high when the "stairs" were at the same height (easy to hide under a chair or side table) and took up about 1' x 1.5' of floor space. It was pneumatic (I think?), so the telescoping pipe thingy between the two foot pads would extend as you stepped down with one foot, and contract as you stepped down with the other foot. However, if you used it for more than about 5 minutes (ie, trying it out in the store), the friction generated heat that made for much less resistance in one direction than the other, so I ended up having to step on the "hard" step with both feet to get it to go down very slowly, and then I could step off it and the other step would come down slowly on its own, or come down very fast (thump!) if I put my weight on it. It became useless very quickly.

I got it on sale, but the original price for it was about $80 about 8-10 years ago, so it wasn't cheap for such a simple machine, either!

Watch out for that kind of mechanism for resistance if you try a similar machine, and try it out for a long time in the store to make sure the resistance continues to affect both sides equally.