FOILCheapest priced copy (Strixhaven: School of Mages): $0.49 at Card Kingdom, near mint, their price list as of .
Fervent Mastery 
Sorcery · Rare · Strixhaven: School of Mages Promos · #101s
You may pay {2}{R}{R} rather than pay this spell's mana cost.
If the {2}{R}{R} cost was paid, an opponent discards any number of cards, then draws that many cards.
Search your library for up to three cards, put them into your hand, shuffle, then discard three cards at random.
Legal inCommanderPioneerModernLegacyVintage
Not legal inBrawlStandardPauper
4 printings · $0.49 to $0.79 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Strixhaven: School of Mages Promos | 101p | Rare | $0.69 | $0.79 |
| Strixhaven: School of Mages Promos | 101s | Rare | — | $0.69 |
| Strixhaven: School of Mages | 101 | Rare | $0.49 | $0.49 |
| Strixhaven: School of Mages | 311 | Rare | $0.49 | $0.79 |
6 rulings from Wizards of the Coast
- 16 April 2021If the {2}{R}{R} cost was paid, the opponent chooses how many and which cards to discard as Fervent Mastery resolves. They may choose to discard no cards.
- 16 April 2021The mana value of a spell on the stack is determined by its mana cost, not any alternative costs you used to pay for it.
- 16 April 2021If you copy a “Mastery” spell and the alternative cost was paid, the copy will resolve as though the cost was paid.
- 16 April 2021If an effect increases or decreases the cost of spells you cast, that cost increase or decrease is applied to the alternative cost you chose to pay. In that case, the cost was still paid for the purposes of the effect, even if you paid more or less for it when it was cast.
- 16 April 2021In a multiplayer game, you choose which opponent takes the prescribed action as the spell resolves.
- 16 April 2021If you choose to pay one alternative cost, you can’t pay any other alternative costs. For example, if an effect lets you cast a “Mastery” spell “without paying its mana cost,” you can’t also choose to pay its given alternative cost.