As said, PT8 support ends with Snow Leopard. Anything that can run that can also run PT8 (but you just cannot install Snow Leopard to a new Mac, needs to be old hardware and that info you can get from
www.everymac.com. Pick the model you are thinking, one of the first information there is the model name used by Apple, for example MacBookPro11,3 and then scroll down the specs and you see "Pre-Installed MacOS: 10.9" which means you cannot install Snow Leopard to that hardware)