Clue
Sylas' eyes shone with a bright light when he saw these three listings. He was also taken aback by the 'Secrets' tag on them. It was the first time he had seen such a thing.
In the end, he chose to exchange for [Introduction to Runes, Rune Patterns and Rune Geometry]. Although he could afford to exchange for World of Runes as well, he still wasn't sure if there was anything else he wanted to buy, and he also felt that though he was eager for improvement, biting off more than he could chew wasn't worthwhile.
Part of maximizing wealth was about not allowing it to sit idly. Sylas wasn't much of an economics major, but his parents ran a business, so he had soaked up a few things with his own almost obsessive attention to detail.