Cheapest priced copy (Commander Legends: Battle for Baldur's Gate): $0.35 at Card Kingdom, near mint, their price list as of .
Javelin of Lightning 
Artifact — Equipment · Common · Commander Legends: Battle for Baldur's Gate · #185
Flash
When this Equipment enters, attach it to target creature you control.
During your turn, equipped creature gets +2/+0 and has first strike.
Equip {4} ({4}: Attach to target creature you control. Equip only as a sorcery.)
Legal inCommanderLegacyVintagePauper
Not legal inBrawlStandardPioneerModern
1 printing · $0.35 to $0.49 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Commander Legends: Battle for Baldur's Gate | 185 | Common | $0.35 | $0.49 |
3 rulings from Wizards of the Coast
- 10 June 2022Javelin of Lightning doesn't enter the battlefield attached to a creature. Instead, the Equipment enters the battlefield and then a triggered ability attaches it to a creature. You may cast Javelin of Lightning even if you don't control any creatures.
- 10 June 2022Attaching 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 the timing restrictions for equip abilities don't apply.
- 10 June 2022If the target creature becomes an illegal target, the Equipment remains on the battlefield unattached.