FOILCheapest priced copy (Final Fantasy): $59.99 at Card Kingdom, near mint, their price list as of .
Buster Sword 
Artifact — Equipment · Mythic · Final Fantasy Promos · #255s
Equipped creature gets +3/+2.
Whenever equipped creature deals combat damage to a player, draw a card, then you may cast a spell from your hand with mana value less than or equal to that damage without paying its mana cost.
Equip {2}
Legal inCommanderBrawlStandardPioneerModernLegacyVintage
Not legal inPauper
3 printings · $59.99 to $229.99 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Final Fantasy | 255 | Mythic | $59.99 | $74.99 |
| Final Fantasy | 351 | Mythic | $119.99 | $229.99 |
| Final Fantasy Promos | 255s | Mythic | — | $179.99 |
3 rulings from Wizards of the Coast
- 6 June 2025If you cast a spell "without paying its mana cost," you can't choose to cast it for any alternative costs. You can, however, pay additional costs, such as kicker costs. If the card has any mandatory additional costs, those must be paid to cast the spell.
- 6 June 2025If a spell you cast has {X} in its mana cost, you must choose 0 as the value of X when casting it without paying its mana cost.
- 6 June 2025You choose whether to cast a spell from among the cards in your hand as Buster Sword's middle ability resolves. You can't wait to cast one later in the turn. Timing restrictions based on the card's types are ignored.