Total Cost

2 Logitech mice - $24
Linksys switch - $15
Cat 6 cables - $22
Padded steel chair (needed to upgrade from steel) - $12
Table from a thrift store - $30
Replacement power supply (the other one was fried) - $50
Speakers - $12
Surge Protector - $18
 I rounded it up to the dollar.

Total: $183


If using this as an example for your own home server, you will possibly need to add the cost of two desktops, and hopefully won't need a extra power supply.

UPDATE: Just a note for the Linux server flavors, I'd highly recommend CentOS it seems to be much more geared towards servers than trying to force Ubuntu or Fedora to act like one.