Running OS X won't be a problem for sure.
MY olde worlde G4/400 ('Yikes') seems to be taking to the new 10.3.4 upgrade like a natural.
It won't be blistering, but presumably you already know that.
Re: the price.
I know (next to) nuthin', though if it's an Apple flat screen, the price does start to sound sweeter.
Not a great help, probably.