On Saturday May 24th, 2014, Pokémon Centers in Japan will be releasing the
Gym Badge Collection Complete Set XY (ジムバッジコレクション コンプリートセット XY). The set of eight badges is a serial number marked limited edition and only 300 will be sold. The set costs 18,334yen each.
The badges will also be sold separately for people that just want get their favorites. The Kalos Region badges will be sold for 463 yen each.
Source:
http://www.pokemon.co.jp/info/2014/04/140425_p03.html