There are 11 total champions that cost 450 BE.
There are 10 champions in free week rotation.
Riot gifts 3 champions.
In order to permanently unlock Draft Pick, I need to unlock 17 champions.
11x450=4950
6x1350=8100
13,050 Blue Essence required to permanently unlock Draft Pick. Reminder, I have 5,080 BE.
The most expensive champions are 6300 BE. I can't even afford to unlock a single 6300 BE champion.
If I use the free week champions. I still need to unlock 7 champions in order to play Draft Pick.
5x450=2250
2x1350=2700
2250+2700=4950
5080-3150=1930
6x450=2700
Even if I use the free week champions, I am unable to unlock a single 3150 champion. If I counted correctly, 104 champions are too expensive for me to play Draft Pick.
EDIT. Forum hijacked my math.