I would usually click the "Hot & New" Tab, which should show you all the discounted items alont with some other non discounted items. You can also check out the Discounted items expiry date on each item listing, the later expiry date items are usually the latest added discounts. Hope this Helps~ 

Under HOT & NEW in the Pearl Shop, click on the SALE tab. ALthough most of the time, if there is a sale, it's on the front page of the Pearl SHop upon opening.