|You can either use documentation like those that are freely available at places like Microsoft's technet or server 2003 and 2008 web pages. All of that is the best if you can find it.|
Another source is the certification courses and books. You can buy the books and read them and use the examples, You don't have to get a certification if you don't want to. The books give excellent examples.
Another place is to look at how companies sell products. The bigger name companies tend to offer examples on their site for how to buy a product. Use them to be able to see your budget choices and maybe suggestions.
Hang up and live.