Cheapest priced copy (Double Masters): $0.35 at Card Kingdom, near mint, their price list as of .
Bloodbriar 
Creature — Plant Elemental · 2/3 · Common · Eldritch Moon · #151
Whenever you sacrifice another permanent, put a +1/+1 counter on this creature.
Legal inCommanderPioneerModernLegacyVintagePauper
Not legal inBrawlStandard
2 printings · $0.35 to $0.49 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Double Masters | 154 | Common | $0.35 | $0.49 |
| Eldritch Moon | 151 | Common | $0.35 | $0.49 |
3 rulings from Wizards of the Coast
- 7 August 2020Bloodbriar's ability is a triggered ability, not an activated ability. It doesn't allow you to sacrifice a permanent whenever you want; rather, you need some other way of sacrificing permanents.
- 7 August 2020If you sacrifice a permanent as part of casting a spell or activating an ability, Bloodbriar's ability will resolve before that spell or ability.
- 7 August 2020A legendary permanent that is put into a graveyard because of the “legend rule” isn't sacrificed.