Cheapest priced copy (Dominaria United): $0.35 at Card Kingdom, near mint, their price list as of .
Frostfist Strider 
Creature — Elemental Giant · 4/4 · Uncommon · Dominaria United · #51
Ward {2} (Whenever this creature becomes the target of a spell or ability an opponent controls, counter it unless that player pays {2}.)
When this creature enters, tap target creature an opponent controls and put a stun counter on it. (If a permanent with a stun counter would become untapped, remove one from it instead.)
Legal inCommanderPioneerModernLegacyVintage
Not legal inBrawlStandardPauper
1 printing · $0.35 to $0.49 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Dominaria United | 51 | Uncommon | $0.35 | $0.49 |
6 rulings from Wizards of the Coast
- 9 September 2022You may choose a creature that is already tapped as the target of Frostfist Strider’s last ability.
- 9 September 2022If a permanent has more than one stun counter on it, only one will be removed each time it would become untapped.
- 9 September 2022Abilities that trigger when a permanent “becomes untapped” won’t trigger if a stun counter is removed instead.
- 9 September 2022If a tapped permanent with a stun counter on it would become untapped, a stun counter will be removed from it instead. This is a replacement effect.
- 9 September 2022Stun counters replace untapping for any reason, including players untapping tapped permanents during their untap steps.
- 9 September 2022If untapping a permanent is part of a cost (such as that of Halo Fountain’s first ability), you may pay that cost by “untapping” a tapped permanent with a stun counter on it. The stun counter will be removed and the creature will remain tapped. However, the cost will still be paid.