I found a handful of sites that appear to still be selling Freakyforms: Deluxe. Obviously I can't guarantee availability or reliability from any of these sellers. US only.

http://www.thegamingwarehouse.com/3ds/nintendo-3ds-games/freakyforms-deluxe-your-creations-alive-for-nintendo-3ds/

http://www.amazon.com/Freakyforms-Deluxe-Your-Creations-Alive-Nintendo/dp/B008YYSBR8/ref=sr_1_1?s=videogames&ie=UTF8&qid=1465018785&sr=1-1&keywords=freakyforms+deluxe

https://www.estarland.com/Nintendo3DS.product.40961.html

https://www.gamefly.com/#!/game/Freaky-Forms-Deluxe-Your-Creations-Alive!/5004587

https://store.nintendo.com/ng3/browse/productDetailColorSizePicker.jsp?productId=prod10627

https://poshmark.com/listing/5144f814c3c9155791015666

http://www.ebay.com/itm/like/391364147319