Yea- the way free software is maintained differs from most (all?) proprietary
systems. You need to really buy hardware with support already taken care of.
And I don't just mean that a driver exists. I mean that it has the chipsets
which have a driver that have hit mainline and are now included in
distributions.
Otherwise even if there is “support” it might be some proprietary driver
or require compiling some piece of code because companies were too cheap to
properly support it and make sure the code ended up in mainline and/or
otherwise got packaged for inclusion in distributions/or distribution
repositories.
What I'm really impressed with is the projects like Freegeek that recycle
systems and ship GNU/Linux (Freegeek is a non-profit in Portland, Oregon). It
is hard enough getting the right hardware and now your digging through
peoples disscarded trash to asemble a complete system that works with free or
mostly free software. The one advantage Freegeek has though is most of the
hardware is already supported or it isn't going to be so it is safe to
disscard (of course you couldn't do that with new hardware quite so easily).