Cheapest priced copy (Commander Anthology): $0.35 at Card Kingdom, near mint, their price list as of .
Cleansing Beam 
Instant · Uncommon · Ravnica: City of Guilds · #118
Radiance — Cleansing Beam deals 2 damage to target creature and each other creature that shares a color with it.
Legal inCommanderModernLegacyVintage
Not legal inBrawlStandardPioneerPauper
3 printings · $0.35 to $0.49 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Commander Anthology | 78 | Uncommon | $0.35 | — |
| Commander 2011 | 116 | Uncommon | $0.35 | — |
| Ravnica: City of Guilds | 118 | Uncommon | $0.35 | $0.49 |
5 rulings from Wizards of the Coast
- 1 October 2005All creatures that share a color are affected, even your own.
- 1 October 2005If it targets a colorless creature, it doesn’t affect any other creatures. A colorless creature shares a color with nothing, not even other colorless creatures.
- 1 October 2005A creature “shares a color” with any creature that is at least one of its colors. For example, a green-white creature shares a color with creatures that are green, white, green-white, red-white, black-green, and so on.
- 1 October 2005You check which creatures share a color with the target when the spell resolves.
- 1 October 2005Only one creature is targeted. If that creature leaves the battlefield or otherwise becomes an illegal target, the entire spell doesn’t resolve. No other creatures are affected.