You should buy a GNU Booted Thinkpad X200 or any other laptop compatible with GNU Boot, and replace the Wi-Fi card with an ath9k one. Any other laptop would contain nonfree blobs and should be avoided, otherwise you would be no different from a typical losedows user.
As for the GNU/Linux distribution, try to stick to a freedom-respecting one. I recommend Trisquel GNU/Linux-libre for beginners, but Gentoo GNU/Linux-libre with
ACCEPT_LICENSE="-* @FREE -Artistic"
is a solid choice too. Don't listen to other meme answers, you should always seek your freedom first above all.