Cheapest priced copy (The Lost Caverns of Ixalan Commander): $0.49 at Card Kingdom, near mint, their price list as of .
Ore-Rich Stalactite // Cosmium Catalyst 
Artifact // Artifact · Rare · The Lost Caverns of Ixalan Commander · #11
{T}: Add {R}. Spend this mana only to cast an instant or sorcery spell.
Craft with four or more red instant and/or sorcery cards {3}{R}{R} ({3}{R}{R}, Exile this artifact, Exile the four or more from your graveyard: Return this card transformed under its owner's control. Craft only as a sorcery.)
{1}{R}, {T}: Choose an exiled card used to craft this artifact at random. You may cast that card without paying its mana cost.
Legal inCommanderLegacyVintage
Not legal inBrawlStandardPioneerModernPauper
2 printings · $0.49 to $0.59 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| The Lost Caverns of Ixalan Commander | 11 | Rare | $0.59 | $0.49 |
| The Lost Caverns of Ixalan Commander | 23 | Rare | $0.49 | $0.49 |
7 rulings from Wizards of the Coast
- 10 November 2023If the card has {X} in its mana cost, you must choose 0 as the value of X when casting it without paying its mana cost.
- 10 November 2023The back faces of some cards with craft refer to cards "used to craft" it. This refers to the cards exiled as part of the cost of the craft ability of the front face. Those cards are considered to be "used to craft" that permanent as long as they remain exiled and the permanent remains on the battlefield, even if the permanent's controller changes or some of its characteristics change (because of a copy effect, for example.)
- 10 November 2023You may exile tokens you control as part of the materials required. However, because they aren't cards and won't stay in exile, any abilities that refer to what you "used to craft" the back faces won't refer to anything.
- 10 November 2023You choose whether or not to cast the exiled card as Cosmium Catalyst's activated ability resolves. If you do, you do so as part of the resolution of that ability. You can't wait to cast it later in the turn. Timing restrictions based on the card's type are ignored.
- 10 November 2023If you cast a card "without paying its mana cost," you can't pay any alternative costs. You can, however, pay additional costs. If the card has any mandatory additional costs, those must be paid to cast the card.
- 10 November 2023If the materials required include multiple objects, you may exile some of them from among permanents you control and the rest from among cards in your graveyard. You don't have to choose all permanents or all cards from your graveyard.
- 10 November 2023If a card that isn't a transforming double-faced card becomes a copy of a card with craft, it'll stay in exile if you activate the craft ability. It won't return to the battlefield.