On ebay they're going for $50-80 or so if they are lucky to sell. Your 800 Ghz can only go to 10.4.11.
If you can successfully erase the HD and it shows up as a valid disk in DU and the OS installer, there may be a problem with the 10.3 installation CD/DVD itself. I forget, does 10.3 run a media scan of the installation DVD?
If you can resurrect it with an install, give it to someone who has no computer or something, or try and sell it for $50.
10.3.9 would be quite dismal with Internet. Firefox helps but it doesn't run everything either.