Every hour, new versions of free software are released for Linux. But it's not necessary to keep up with the flood, except serious security updates, which are released usually within a day or two of a security bug being found. Linux books are cheaper and often more informative than WinNT books. Linux consultants are likely to be cheaper. They are also likely to perform tasks faster.
Online support is free.
RedHat offers commercial support, free for the first 90 days. Hardware for Linux is cheap. Most PC hardware works with Linux. For graphical administration, a Pentium with more memory is better. A Pentium also speeds up file sharing.