Cheapest priced copy (Kaldheim): $0.35 at Card Kingdom, near mint, their price list as of .
Giant's Amulet 
Artifact — Equipment · Uncommon · Kaldheim · #59
When this Equipment enters, you may pay {3}{U}. If you do, create a 4/4 blue Giant Wizard creature token, then attach this Equipment to it.
Equipped creature gets +0/+1 and has "This creature has hexproof as long as it's untapped."(It can't be the target of spells or abilities your opponents control.)
Equip {2}
Legal inCommanderPioneerModernLegacyVintage
Not legal inBrawlStandardPauper
1 printing · $0.35 to $0.49 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Kaldheim | 59 | Uncommon | $0.35 | $0.49 |
2 rulings from Wizards of the Coast
- 5 February 2021You decide whether to pay {3}{U} as the enters-the-battlefield ability resolves. If you do, you immediately create the Giant Wizard creature token and attach Giant's Amulet to it. No players may respond to your decision to pay or not, and no player may take actions during this process.
- 5 February 2021The Giant Wizard creature token enters the battlefield as a 4/4 creature. Any abilities that trigger when a creature with a certain toughness enters the battlefield will see the token enter as a 4/4 creature.