advice sought on how to setup small network of linux hosts...hardward and software?

[Walter Tautz <wtautz@math.uwaterloo.ca>]

basically a handful of boxes....perhaps a beowulf or fai cluster which will
be connected to the outside world at some point using NAT?

I've heard it's possible to get some network hardware (switches, hubs?)....
for a very low price and with some decent quality....I must confess to
being a novice when it comes to setting up such a network .... any
advice on hardward and software configuration advice would be appreciated.