$400 - $500 minimum? :lol: Sure, if it was absolutely MINT, boxed and hadn't been previously molested by 10 different owners, maybe.
The $200 figure is pretty accurate for ebay (I've seen several in similar condition sell for less within the past year). There are far too many "unknowns" in this case for anyone to drop $500, IMHO, and there appears to be a fair amount of yellowing on the keyboard and front bezel.