https://developers.redhat.com offers a range of wonderful resources, including the ability to use Red Hat Enterprise Linux for free, with access to updates from our content delivery network.
See this article for more information: https://developers.redhat.com/products/rhel/download/
Please correct me if I am wrong, but this is THE WAY to have 'free' RHEL systems in an organizaiton that also has subscriptions for production servers. Remember toe EULA requires you to have ALL your RHEL installations covered by a subscription.
Please note that for a Developer account your Login ID (aka RHN id) must be at least five characters long.
In case your Login ID is shorter than five characters (I've got one) you must create a new Login ID. Please note you can't create new shorter than five character Login ID's.
"Free" is our favorite price point! I've been telling my developers about this opportunity for a long time now. I'm still amazed many people aren't aware it exists.
I would also suggest that people dabble with CentOS. It is largely the same UI and steps as RHEL, minus a few things that RHEL does specifically to enable the support and update model they offer.
CentOS will expose users to some slightly different ways of doing things (configuring different Yum mirror repositories comes to mind.) It's good to diversify, and if you are brave Fedora is always good for some possible "Coming Attractions" from future releases of RHEL.