Cheapest priced copy (Foundations Jumpstart): $0.35 at Card Kingdom, near mint, their price list as of .
Cliffhaven Kitesail 
Artifact — Equipment · Common · Foundations Jumpstart · #748
When this Equipment enters, attach it to target creature you control.
Equipped creature has flying.
Equip {2} ({2}: Attach to target creature you control. Equip only as a sorcery.)
Legal inCommanderPioneerModernLegacyVintagePauper
Not legal inBrawlStandard
2 printings · $0.35 to $0.49 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Foundations Jumpstart | 748 | Common | $0.35 | — |
| Zendikar Rising | 243 | Common | $0.35 | $0.49 |
2 rulings from Wizards of the Coast
- 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.
- 25 September 2020If the target creature becomes an illegal target, the Equipment remains on the battlefield unattached.