As part of the anniversary celebrations, 3 sets of Rainbow Coins are on discount. The first two sets can only be bought once. The third set (70 coins for 3.800 yen) can be bought up to 5 times.
Limited-time items at special Diamond prices have also been added to the Exchange Center. They are marked with “remaining: 16 days” as shown here. Make sure to grab the ones you want before they go away!