Cheapest priced copy (Secrets of Strixhaven Promos): $0.49 at Card Kingdom, near mint, their price list as of .
Molten-Core Maestro 
Creature — Goblin Bard · 2/2 · Rare · Secrets of Strixhaven · #125
Menace
Opus — Whenever you cast an instant or sorcery spell, put a +1/+1 counter on this creature. If five or more mana was spent to cast that spell, add an amount of {R} equal to this creature's power.
Legal inCommanderBrawlStandardPioneerModernLegacyVintage
Not legal inPauper
3 printings · $0.49 to $0.79 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Secrets of Strixhaven Promos | 125p | Rare | $0.49 | $0.49 |
| Secrets of Strixhaven | 125 | Rare | $0.49 | $0.49 |
| Secrets of Strixhaven | 335 | Rare | $0.79 | $0.79 |
2 rulings from Wizards of the Coast
- 20 March 2026An opus ability resolves before the spell that caused it to trigger. It resolves even if that spell is countered or otherwise leaves the stack.
- 20 March 2026Molten-Core Maestro's last ability is not a mana ability. It uses the stack and can be responded to.