"As previously reported, custom themes are coming to the Nintendo 3DS and Nintendo 2DS. These will be based on various games for the platform, and you’ll be able to purchase them from an online store through the system itself. This week, Nintendo updated their website in Japan with a look at some of the themes being released.
Themes vary in price, too. The Gunvolt themes range from 100-150 yen each, while Yo-kai Watch and Monster Hunter are 200 yen apiece."