Deals can be found in the Store menu (N). There are three types of deals, Weekly Deals, Flash Deals and Power Deals.
Weekly Deals rotate in a weekly biasis, and are available once per month. Some of them contain exclusive items, such as Double Experience Potions and Golden Dragon Effigy.
Flash Deals appear in the store every 4 days, and they last 4 hours. They offer 5x value on the original price of various consumable items essential to powering up.
Power Deals (Prices not confirmed)
Power Deals are unlocked as the player gets higher Power Rank, and they appear for 6 hours. They offer 4x value on the original price of various items.