Cheapest priced copy (Weatherlight): $0.35 at Card Kingdom, near mint, their price list as of .
Briar Shield 
Enchantment — Aura · Common · Weatherlight · #121
Enchant creature
Enchanted creature gets +1/+1.
Sacrifice this Aura: Enchanted creature gets +3/+3 until end of turn.
Legal inCommanderLegacyVintagePauper
Not legal inBrawlStandardPioneerModern
1 printing · $0.35 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Weatherlight | 121 | Common | $0.35 | — |
One ruling from Wizards of the Coast
- 1 April 2008When you cast Briar Shield's activated ability, Briar Shield is put into the graveyard as a cost. The +1/+1 effect immediately ends, but the +3/+3 effect won't begin until the ability resolves. The enchanted creature gets no bonus while Briar Shield's ability is on the stack. If its toughness is 0 during this time, it'll be put into the graveyard.