I remember when I first started to learn some different technologies. It required that I have several servers so that I could learn more than the basics.
For example, if you want to learn ISA Server, you would need an external client, an internal client, the ISA server, the domain, and another internal server to practice publishing. Oh, you want to test configuring access from the Internet to your Exchange environment? OK, add a couple of more servers, after all, won't you want to also play with Exchange and configure a Front End and Back End environment?
Exchange was a real killer. I needed multiple FEs and BEs, I needed bridgehead servers, and an AD environment.
Oh yeah, and because I was a self-employed, I also had my production network with my production email, website, and so forth.
So, about 18 months ago, I counted the desktops and real servers (yeah, server class machines costing me lots of money) in my home network. Total = 18. Total cost = $38,000 and some change. No, I did not share that with my wife. No, I did not tell my Mom or Sister.
Now, if I want to test building a couple of Exchange or SQL clusters, it is no big deal. Not only does it take me about two minutes to build a new server (since I have a couple of base images), then I can do it all within Virtual Server 2005 R2. I used to also use Virtual PC 2004 a great deal for one-off testing.
Now, I am down to 7 computers in my home network of which five are client computers (a couple of laptops, included). Wow, life is much better and certainly less complicated.
The good news? You can do it, too. Virtual PC and Virtual Server are both free products from Microsoft. Download them, play with them, learn them, and save time and money.