Or this one.
PowerMac G4 800 MHz
Apple Power Mac G4
800MHz 256MB Ram Mac OSX 10.3.9
DVD/CDRW
40 GB INTERNAL DRIVE
Applications Include Adobe CS (Photoshop,Illustrator, InDesign, Acrobat Professional), GoLive, Microsoft Office.....etc
Keyboard & Mouse, Original User Guide/Cd's
Great Condition, great performance $400obo
In my humble opinion, it seems strange for somebody to include adobe CS suite for that price. That's a pretty expensive software package I'd guess, even if it is 2 versions behind.
Anyway, why don't you consider a NEW mac mini? They don't come installed with a ton of memory by default, but they are new. The base model is 100 bucks over your budget, but I bet if you saved for a bit longer (depending on your income) you could afford one. And, if you took a bit longer to save the money, maybe you could even wait for the october release of Leapord, and you'd have everything for not too much more...
And you'd have a warranty, and that fuzzy feeling you get when you buy a new apple product
Though, no dedicated video card means some of the higher end video editing software might be a bit more painful to work with..