Mac Powerbook G4 Repair Issues...

Inherited a 3 year old notebook from my brother that used to be a monster of a machine 3 years ago...Powerbook G4 Aluminum, A1046...Not sure of the processor speed which is the result of my problem...Display is not working and the keyboard needs to be replaced.

Genius Bar at Apple Store says that Mac could do the repair for nearly $900 but that websites etc. offer competent repair for nearly half that.

I'm just curious what are the thoughts on repairing a notebook like this (Just going to use it for WiFi surfing, word processing etc.)for around $400-$500?...Is it worth it to do that at this stage?...My brother says not really...Also, wondering if I bought a used keyboard and display off of ebay or someplace for less, is it simple to have someone install it or do it myself?...I think maybe that could cut it down to only a couple hundred dollars and that would be worth it, non?

Thanks for any help.