Cheapest priced copy (Commander Masters): $13.99 at Card Kingdom, near mint, their price list as of .
Sapphire Medallion 
Artifact · Rare · Tempest · #306
Blue spells you cast cost {1} less to cast.
Legal inCommanderModernLegacyVintage
Not legal inBrawlStandardPioneerPauper
7 printings · $11.99 to $37.99 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Commander 2014 | 266 | Rare | $15.99 | — |
| Commander Masters | 407 | Rare | $13.99 | $12.99Out of stock |
| Commander Masters | 614 | Rare | — | — |
| Modern Horizons 3 | 296 | Rare | $13.99 | $11.99 |
| Modern Horizons 3 | 349 | Rare | $19.99 | $37.99Out of stock |
| The List | TMP-306 | Rare | $19.99 | — |
| Tempest | 306 | Rare | $27.99 | — |
5 rulings from Wizards of the Coast
- 28 July 2023If a spell you cast has {X} in its mana cost, you choose the value of X before calculating the spell's total cost.
- 28 July 2023If there are additional costs to cast a spell, or if the cost to cast a spell is increased by an effect (such as the one created by Thalia, Guardian of Thraben's ability), apply those increases before applying cost reductions.
- 28 July 2023The ability doesn't change the mana cost or mana value of any spell. It changes only the total cost you pay.
- 28 July 2023The cost reduction can apply to alternative costs such as flashback costs.
- 28 July 2023The ability can't reduce the amount of colored mana you pay for a spell. It reduces only the generic mana component of that cost.