Numerous store sales and special promotions occur with or without Nintendo's consent.
I've purchased Fire Emblem Awakening for $15, Paper Mario Sticker Star for $10, Pokemon X for $30, and Kingdom Hearts 3D for $20.
All New too.
Only game I've paid full price is Bravely Default because I pre-ordered the collector's edition.
A sale for Yoshi's New Island is feasible considering the fact that even a dollar, two or three saved can net me 4-5 games off of another platform (i.e. Steam via humble bundle)