A Linux install would be a lot cheaper than a Mac..
free in fact...
open source - can be downloaded burned to a DVD and a live DVD created so you can try it from DVD drive before installing. Burn it at a slow setting or it may have errors.

I completely ditched windows on an older laptop and Linux Lubuntu is on it now.
Less bloat and rarely any issues with viruses.

my favs -
Ubuntu, KDE, Mepis, PCLinuxOS, Lubuntu, Puppy


http://distrowatch.com/dwres.php?resource=major

Some can be found in Linux magazines, as well as some live cd's in some Linux library books.

something to think about for an older slow windows computer, unless you have a lot of purchased software that requires windows operating system.

But it would be hard to talk someone thru setting Linux up if they ran into problems long distance.. Some "distros" will find the wireless signal right away , but some need a bit of tweaking..
I would suggest trying some of the live cd/DVD versions before thinking of installing any ...to see if you like it and that is connects easily to go online.
I had a spare computer to look up things online when I had questions about something,

But that is a whole other topic...