Linux isn’t that hard. Grab and old desktop and play around with it if you can. I’d suggest Debian – it has more of a learning curve but it’s also more consistant. And by consistant I meant that once you learn how to configure one program, you can configure all of them (unlike RedHat with all of its proprietary garbage … but I digress).
Actually, two of my servers are old desktops. Two Dell XPS D series chassis motherboards and et cetera, so there’s nothing wrong with using an old desktop for doing that.