Used apple 2015 apple imac. I bought it to use as a second monitor because the retina displays is the only monitor I’d used for extended periods without my eyes aching. I did very little research, bought a used one to find out, nope you can’t hook it up as a second monitor and the hardware is awful
https://blog.lewislovelock.com/turning-an-5k-imac-into-a-mon...
You can convert them to monitors, if you want.
Apple stuff seems to have the biggest difference in usefulness between new and used. The new stuff is usually really great, but as soon as they cross some "too old threshold" they quickly become next to useless because of how closed everything is and because Apple (and, shamefully, third party developers) don't keep up software support and backward compatibility. I've got a bunch of 8+ year old iDevices and Macs and they are all of varying degrees of uselessness as Apple and the whole ecosystem has abandoned them.
Agreed! I wish Apple was more thoughtful about generating so much e-waste. The Mac Pro Tower (2006-2012) is a great example of where I thought they might have been on the right track.