Damn, old Intel Macs are ridiculously cheap second hand. Like thinkpad cheap.
AFAIK they are really well supported by Linux.
I guess the only downside is the weird Apple bullshit of yore.
On the extreme you can get a 2013 Macbook Pro or Air in very good condition for £50.
More modern, you can get 2017 era for £150.
Goo Truther 
@kawaiipunk don't get stuff earlier than 2014-ish there is a whole nightmare mess of unorthodox bootloader setup and possibly even Apple firmware updates that are required. I have been mired by this for 3 years with a secondhand Air I got.
@thufie ah I have a 2012 Air and it seems fine afaik. Thanks for the tip!!
@kawaiipunk maybe I am just uniquely cursed because the original owner never ran updates.
@kawaiipunk I may actually be interested in a disk image of that Mac Air...
@kawaiipunk bootloader literally a different architecture than the actual system it boots on this thing and it is a trainwreck.