Friends teach what you want to know. Enemies teach what you *need* to know.

Rhystic Study

Whenever an opponent casts a spell, you may draw a card unless that player pays {1}.

"Despite her father's warnings, Valtry's fascination with the surface only grew. She collected things that fell to the bottom, daydreaming of life on land."
—*The Merfolk Who Walked*

Wilds of Eldraine: Enchanting Tales

"I'll teach you the leyline paratrigonometrics, no problem. But you need to show me how to make that fiery swirly thing."
—Zimone, to Rootha

Jumpstart 2022

"I believe I've discovered something truly incredible: a way to harness magic through science!"
—Jayce Talis

Secret Lair Drop

Rhystic Study's triggered ability resolves before the spell that caused it to trigger. It resolves even if that spell is countered. The player gets the option to pay when this triggered ability resolves.

You don't have to decide whether or not to draw a card until after the player decides whether or not to pay.