Cheapest priced copy (Explorers of Ixalan): $0.49 at Card Kingdom, near mint, their price list as of .
Threads of Disloyalty 
Enchantment — Aura · Rare · Betrayers of Kamigawa · #56
Enchant creature with mana value 2 or less
You control enchanted creature.
Legal inCommanderModernLegacyVintage
Not legal inBrawlStandardPioneerPauper
4 printings · $0.49 to $21.99 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Betrayers of Kamigawa | 56 | Rare | $0.69 | $5.99 |
| Explorers of Ixalan | 11 | Rare | $0.49 | — |
| Amonkhet Invocations | 37 | Special | — | $21.99 |
| Signature Spellbook: Jace | 8 | Rare | $0.49 | $0.99 |
3 rulings from Wizards of the Coast
- 1 February 2005Creatures on the battlefield treat {X} in their mana cost as 0 for the purposes of calculating mana values.
- 1 February 2005Tokens usually have a mana value of 0.
- 1 February 2005Threads of Disloyalty can't target a creature with mana value 3 or greater. If it somehow enchants a creature with mana value 3 or greater, Threads of Disloyalty is put into the graveyard the next time state-based actions are checked.