Having almost choked at the cost of shop bought ones, I glued & screwed a 3'
high 2"x3" length of timber to a baseboard of 6mm Ply which had a carpet
tile glued & stapled to it. I almost wet myself after I'd wound a length of
nylon rope (6mm dia) around the timber to create a ?25 NECESSITY for a
little under ?5.

I don't know what the cats like best about it, is it flicking & chasing the
pin pong ball that hangs by a thread from the top, trying/succeeding to tug
the threads from the carpet, sitting on top of it to watch cat TV (fish
tank), or lazily stretching their backs whilst dragging the full might of a
fully extended set of flick knives down the corrugated texture of the wound
rope?

And it's almost as well used as the furniture !