Skies of Arcadia is one of the best games released for the Sega Dreamcast. It's a fun role-playing game with flying ship, floating islands and Sky Pirates. What's not to love?
Amazon.com, eBay, craigslist, garage sales, thrift stores, pawn shops, or your local used video game store (such as Gamestop) to find a copy. I managed to find my copy at a local pawn shop for $10 but if you keep your eyes open you never know where you might run across it. Good Luck!