Like most Magic: The Gathering cards, the value of Rhystic Study depends on a few consistent factors: its rarity, the printing and finish (regular or foil), its physical condition, and the set it was printed in (Final Fantasy: Through the Ages)
Let's try that again and see if we can find any non-10-mana, non-$50 cards, shall we
Nowadays, Commander is the primary way for casual Magic to be played
If this card is Special Summoned: You can send the top card of your Deck to the GY, then target 1 Level 4 or lower WATER monster in your GY, except "Deep Sea Artisan"
You can draw heaps in one turn, even without Superancient, with the help of Remora + Angler + XYZ Change combo
Until official pull rates and print details emerge, treat singles as the speculative play and sealed as the steadier hold