This shop sells various items and heroes though it’s only limited to 6 random items at a time. You can refresh the list by paying 50,000 Gold once a day where the entire list will be replaced by randomly selected items. You should always buy Insignias, Evolvemons, and Essences since they’re worth their price. Of you have a lot of gold to space, you can even buy R-grade heroes to use as Evolution fodders. The secret shop has its own refresh timer and won’t be affected by the schedule daily reset.