In about a week, you can buy 10 SR and 10 SSR books from each Advent. That will seriously help you MLB everything that you want to MLB.
150+100+50+50 10 SR books (10)
0+250+200+100 SSR books (10)
Total cost of them. Not that bad, considering how SSR Eidolon and Weapon costs have been entirely gutted (like how raid content went down from 200 -> 50 required Souls).