I bought a second-hand Macbook off of Ebay, which was very easy to flash with
Libreboot. It can be done with a command line tool, without needing any
special hardware. I had probably spent around $200 on it, by the time I
bought a new battery and fan, but it's a great machine and runs very well
with Trisquel 7 and LXDE. I would recommend it to anyone.
In general though, I agree with the OP. It seems that the real issue for free
software these days is not software, but hardware. It seems that we have
free-software equivalents for almost everything you might want, but
compatible hardware is a very different story. The big problem with hardware
is that is requires $$ investment, at a different level to software, and it's
hard to see where those $$ are going to come from.
I also have a lot of hopes for EOMA and Power9, which are looking very
promising. Hopefully crowdfunding will prove to be a powerful tool to help
advance the frontier of free-software-supporting hardware.
