Careful when buying monitors for Unix workstations, some of them are fixed frequency and won't work with standard PC video cards. I am not sure if this applies to the one you are purchasing. It's just an issue that wouldn't even occur to most PC users. This is more tha case with older monitors than newer ones, but still applies to some newer ones.
[Edit: Basically, everyone I know who has gotten their hands on a Sun 21" monitor -- even free, they have always ended up in a closet or passed to someone else.]