Ripped off?

So I bought this G4 Powerbook from one of my friends yesterday. He said since it was his dad's, he couldn't log onto the admin name, but the computer restarted to a guest account. He gave me a discount, at $150.00. So naturally I took it home and fixed it to my own settings, and made an admin account. I want to sell it now, but I'm not sure what it's worth. Here are the specs:

Machine: PowerBook G4 15"
CPU: PowerPC G4 (1.1)
CPU Speed: 1.33 GHz
L2 Cache: 512 KB
Memory: 512 MB
Bus Speed: 167 MHz
Boot ROM Version: 4.8.4f1

I have the power cords, etc. It's a little dented at some points, but still looks damn good. It uses Mac OS X. Oh, and it has 57.3 GB left, after I deleted everything that was unnecessary. Can someone give me an idea how much it's worth?

Seriously, one dollar, that's what I would buy it for.