Cheapest priced copy (Khans of Tarkir): $0.35 at Card Kingdom, near mint, their price list as of .
Singing Bell Strike 
Enchantment — Aura · Common · Khans of Tarkir · #55
Enchant creature
When this Aura enters, tap enchanted creature.
Enchanted creature doesn't untap during its controller's untap step.
Enchanted creature has "{6}: Untap this creature."
Legal inCommanderPioneerModernLegacyVintagePauper
Not legal inBrawlStandard
2 printings · $0.35 to $0.49 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Khans of Tarkir | 55 | Common | $0.35 | $0.49 |
| The List | KTK-55 | Common | $0.35 | — |
2 rulings from Wizards of the Coast
- 20 September 2014Singing Bell Strike can be cast targeting any creature, including one that's already tapped.
- 20 September 2014The activated ability that untaps the creature is granted to the enchanted creature. Only the creature's controller can activate this ability.