Kobo has a coupon code for 50% off this list of books and it looks like the Cassie Pengear Bundle is one of the books included.  The coupon code is JAN1650 and is good from Jan 28, 2016 to Jan 31, 2016 in the Canada, United States, Australia, New Zealand, and the United Kingdom stores.  It’s a Kobo promo, not one I set up, so you’ll have to direct questions to them.