Pokemon Rumble is a spin-off Pokemon game, that only costs 1500 Wii Points (which some people see as a lot).
It doesn't feature all the Pokemon (those from Johto, Hoenn or Unova (because Unova wasn't invented back then)), but it's a very awesome game! Go watch some YouTube videos for more information, or just wait for my full guide to come out (though it might take some time).