You can purchase Crash Nitro Kart for the gameboy advance for £7.99 from play.com - this is a good price for a wee stocking filler of a game. A quick price search shows this to be £25 at amazon!!
Review: Crash hits the track in his most fast-paced adventure yet - Crash Nitro Kart! Kidnapped by the ruthless Emperor Velo and forced to race in his galactic coliseum, Crash must race his way to victory in order to save the Earth from destruction - but it won't be easy, as he must compete against foes both old and new before a final showdown with Velo himself! Crash Nitro Kart leads the pack by mixing awesome next-gen graphics and gameplay with the playability and fun of classic kart-racing games.