I reached the 3k mark, then they give new 4 peak rewards. Cores are in that classment. So I would say you have to pass the 3k mark, resulting me in putting atleast 1700 comps = 17*3 = 51 euros. About 102 euros rougly calculated to reach the 6k mark to guarantee the legendary cores from AH (really not worth it) and the 14 days - FOURTEEN DAYS HAHAHAH petrified core when reaching 6k mark, meaning it is MINIMUM 80 euros for a 2 week petri core. Not even seeing subtime myself, guessing it's for after the 6k mark, going towards 9k mark = 150 euros. A complete joke. Remove the timed items in subscription server.
Sidenote, grail lv5 does not affect prophetic card drops. Be more clear in your explainations on buffs, my.games. I know you will read this in a flight in a year or so, or when everything died already. Tip of the hat!