Answers:
It depends on what you do next to it.
But, you can own Microsoft's Virtual Server 2005, and Virtual PC 2007 for free, if you merely look into them out and download them from Microsoft's website.
difficult to read aloud unless you speak about us what you want to serve!!
Only The Cost of the Hardware VMWARE server is free and can be downloaded from the website.
You do involve a serial but you acquire the for free from the VMWARE website when you register