Is Red Hat Enterprise Linux free?
Yes and no. The source code is available for almost all
programs, and is made available in unofficial and semi-official
form as CentOS and Fedora, respectively. However, RHEL, when
branded as such, is only available through purchasing a support
plan.
Red Hat had two versions of Linux, one for home/consumer/desktop
use, and one for commercial/enterprise/server use (Red Hat
Enterprise Linux).
A few years ago, Red Hat decided to focus only on RHEL. The
consumer/desktop version was renamed Fedora and given to the
community to support.
If you are looking for an older version of Red Hat, you can
Google the specific version you are looking for and a number of
mirrors will appear - but I would recommend against this, it's no
longer supported or updated, and you'll probably have issues with
it and newer hardware.