Linux and Apache can both be obtained free (for Commercial and Personal use), however, I HIGHLY recommend that if they go this route to get you training in managing Apache/<whatever OS you end up using> -- it will be worth the cost in the long run. You can find out more about Apache's License at http://www.apache.org/licenses/
For Linux, there are both Commercial abilities (so you get Support), and complete you install it and you support it (thus free) options. Support can be a BIG deal for companies, that's one reason Microsoft excels, but there are a number of good Linux vendors who do equally well in this area. Red Hat, Ubuntu are the two big names I know of (I'm sure there are others). Fedora, CentOS, and Debian (my personal choice) are all free (but there is a huge learning curve to Linux, so be warned).
I should also mention there is a TON of free support forums out there around the Linux/Apache community, so if you get stuck, you usually just have to search for a forum and post a question. You might not get an answer immediately (whereas, paid support, you might), but you'll get one eventually.