Cheapest priced copy (Throne of Eldraine): $0.35 at Card Kingdom, near mint, their price list as of .
Crystal Slipper 
Artifact — Equipment · Common · Throne of Eldraine · #119
Equipped creature gets +1/+0 and has haste.
Equip {1} ({1}: 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 |
|---|---|---|---|---|
| Throne of Eldraine | 119 | Common | $0.35 | $0.49 |
One ruling from Wizards of the Coast
- 4 October 2019If a creature enters the battlefield under your control and gains haste, but then loses it before attacking, it won't be able to attack. This means that you can't use one Crystal Slipper to allow two new creatures to attack in the same combat.