Upcoming Pokemon 3DS Game will have Free DLC for the First Month
For one, there is a downloadable content. For the first month, the DLC dungeon named "PokeForest" will be free for the first month. After that, it will be available for 2$.
There will be other dungeons. The game's coming out on March 24. If you happen to not have any retail store near you, you can always check out the eSHop because it will be available there at launch.\
Pokemon Mystery Dungeon: Gates to Infinity was released in Japan last November 2012. Check out its cute Japanese preview.