If you are looking for the official retail price of the game for the Nintendo 3DS:

As this is a digital file typically hosted on ROM-sharing websites like Ziperto, it does not have a "price" in a legal or retail sense. These files are generally distributed for within the emulation community, though downloading them may infringe on copyrights held by Nintendo.

is now closed for new purchases, meaning the digital version can no longer be bought directly from Nintendo.