Not really, while I wouldn't consider it a completely absurd price. (I have seen PowerBooks be posted and actually sold for over $200 on my local craigslist) I personally wouldn't pay that much, 10.8 Mountain Lion just came out, putting this PowerBook THREE versions behind the current Apple Operating system. (The PowerBook's max is OS X Leopard 10.5.8)
If it was maxed out with 2GB of ram, had Leopard on it, (and included the install disks) I would personally offer around $75 max for it. They're still useful for basic web browsing, email, Facebook, stuff like that. Online video and Flash Games you should forget about right now, they'll lag like crazy on an older machine like this.
Overall, it's really up to you on how much you want to spend on an aging obsolete laptop.