Cheapest priced copy (Kamigawa: Neon Dynasty Promos): $1.79 at Card Kingdom, near mint, their price list as of .
March of Otherworldly Light 
Instant · Rare · Kamigawa: Neon Dynasty Promos · #28p
As an additional cost to cast this spell, you may exile any number of white cards from your hand. This spell costs {2} less to cast for each card exiled this way.
Exile target artifact, creature, or enchantment with mana value X or less.
Legal inCommanderPioneerModernLegacyVintage
Not legal inBrawlStandardPauper
5 printings · $1.79 to $6.99 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Kamigawa: Neon Dynasty | 28 | Rare | $1.99 | $2.49 |
| Kamigawa: Neon Dynasty | 369 | Rare | $2.99 | $6.99 |
| Kamigawa: Neon Dynasty | 441 | Rare | $2.49 | $5.99Out of stock |
| Kamigawa: Neon Dynasty Promos | 28p | Rare | $1.79 | $3.99 |
| Kamigawa: Neon Dynasty Promos | 28s | Rare | — | $5.49 |
3 rulings from Wizards of the Coast
- 18 February 2022For example, say you wanted to choose a target with mana value 6. You need X to be at least 6. You could choose to cast March of Otherworldly Light by paying {6}{W}. You could also exile white cards from your hand to reduce that cost by {2} for each one. If you had a reason to, you could even choose a greater value for X.
- 18 February 2022The mana value of March of Otherworldly Light while it's on the stack is the value chosen for X plus 1, no matter how much mana you actually paid to cast it.
- 18 February 2022You may exile more cards than necessary for March of Otherworldly Light's first ability, but you can't reduce the mana it costs to less than {W} this way.