Cheapest priced copy (Zendikar Rising): $0.35 at Card Kingdom, near mint, their price list as of .
Utility Knife 
Artifact — Equipment · Common · Zendikar Rising · #256
When this Equipment enters, attach it to target creature you control.
Equipped creature gets +1/+1.
Equip {3} ({3}: Attach to target creature you control. Equip only as a sorcery.)
Legal inCommanderPioneerModernLegacyVintagePauper
Not legal inBrawlStandard
1 printing · $0.35 to $0.49 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Zendikar Rising | 256 | Common | $0.35 | $0.49 |
2 rulings from Wizards of the Coast
- 25 September 2020If the target creature becomes an illegal target, the Equipment remains on the battlefield unattached.
- 25 September 2020Attaching an Equipment with its enters-the-battlefield triggered ability isn't the same as using its equip ability. You don't pay mana for the attachment, and if the Equipment enters at a time you couldn't cast a sorcery, you can still attach it to a creature you control.