"We'll begin our attack on the ants tomorrow so until then, we will prepare our own things" came Cold Mountain's voice. Hearing it, everyone agreed with his suggestion. So, without any further ado, they dispersed and left in different directions.
Everyone had a different purpose. And Cylius' was the skill library.
...
"How much are the attribute crystal balls?"
"Two silver. Comes with a manual on how to use it if you buy it"
"I'll take one"
After coming into the library, he bought an attribute crystal ball. It wasn't cheap but considering this was an essential item in becoming a mage, he didn't hesitate to buy it.
After all, using a skill of their own attribute would have quite a few advantages while using those of the opposite attribute could even result in some deboosts and disadvantages. So he can't just aimlessly buy skill books of any attribute mindlessly.