If you have many low level Training Scrolls, you can exchange them at the Black Market for higher levels.
-Lv. X Training Scroll * X + Augur's Seal * 10 = Lv. (X + 1) Training Scroll
-Which means: You can exchange two Lv. 2 Training Scrolls for one Lv. 3 Training Scrolls, three Lv. 3 Training Scrolls for one Lv. 4 Training scroll, and so on.