If you want to start learning about web servers et all, there are 2 other options (putting your site on an outside host is probably a good idea, but nothing stopping you from learning this side of things either!)
- a VPS (virtual private server) I have 2, and they're pretty good sandboxes. My hosting company bothers with security, but I still have a great deal of control. They're a good midrange option for someone who needs more then the usual shared hosting and doesn't need (or want) full dedicated. Not free.
- run a VirtualBox guest. This will let you run an OS inside an OS, and you can interact with the "guest" server like any normal server, depending on how you configure it. Free.
If you really want to have a server-server, go for it! Just be aware that getting one to run is easy. Making it safe is not.
Just make sure that your own personal data is secured elsewhere. You can use old crummy computers to be basic servers. I have an old Dell desktop that retired to life as a DNS server on our private intranet. It was a hunk of junk for desktop use, but for sitting there playing "traffic cop"? It's a champ.