Though it may not necessarily be widely used on a daily basis, Nintendo Badge Arcade has been a fun extra on the 3DS. The free-to-download app - with various microtransactions thrown in - offers a chance to win badges through a simple crane game, which can then be used to spruce up the system's HOME page.
The pricing on plays and related special HOME Themes can be considered a bit high, though, so some discounts are running to celebrate the one year anniversary of the app. In Europe the deal is simple - two free plays per day, half price on purchased plays, and by extension a free Theme at a cheaper price when you buy 10 plays for £0.90.
In North America it's a bit different. The discounts end on 17th October, with two free plays still to come on 14th November (it's not a daily offer).
It may be worth jumping in for free plays if nothing else, just to see that strange pink rabbit - it has a quirky character.