That is a huge question, possibly only topped by ‘hand tools or machinery, which should I get in to?’
Probably the critical thing is that it depends if in addition to the stools, you want to: process 4x8 plywood sheets; 3D engrave jewellery quality forms in precious metals; do 4 or 5 axis work; etc. No machine does everything.
I find comparing the idea to cars to be quite relevant: do you want a truck, sports car, family saloon; how much time with each? For most people having a ‘car’ most of the time but occasionally renting a van or track-day car makes sense, but you don’t have to spend it all on one machine; you might have to buy 2x £1,500 machines to achieve what you want.
Do you want the cnc machine to be a hobby in itself (building it up from hundreds of parts having sourced to the right spec) or updating a old machine that has a great, rigid frame from the late 90s/early 2000s?
‘Kids stools’ could be finely carved with cnc cut joints, or entirely flat cut from sheets.
The adaptability and work-holding are critical questions. Your inclination to build from a kit and problem solve versus your need for high quality customer service on a ready made machine.
I was looking at buying a machine about 18 months ago, and this was my impression:
Avid CNC is very popular with Youtube wood workers. Made in USA, gets expensive quickly.
Ooznest seems to be a popular UK based DIY version that is cheaper but less rigid. This was my second choice.
I seriously considered a Blue Elephant machine direct from China, but in the end didn’t want to deal with the customs forms. That would have been a real work horse.
There are many ‘light weight’ machines out there, such as the X-Carve or the kits direct from China via ebay and BangGood.
In the end I decided I wanted a welded steel frame (not aluminium extrusion), with ball screws and a proper water-cooled spindle rather than a router. The one I bought was the 1mx0.65m version from this ebay shop:
Items for sale by startup101 | eBay
I was able to see the machines running and they built one for me in a few weeks. Over a year on and I’m very happy with it.