If you still don't own a copy of Sonic Adventure, you can get one for 20 bucks from Mplayer.com as a special offer to its members. I'm not sure if you have to be a member or not, but it's there and only $20 (US dollars) from the List Price of $57.99! Here's the URL:
http://store.mplayer.com/...
Source: Mplayer Store Newsletter
