Cheapest priced copy (Homelands): $0.35 at Card Kingdom, near mint, their price list as of .
Sengir Bats 
Creature — Bat · 1/2 · Common · Homelands · #57b
Flying
Whenever a creature dealt damage by this creature this turn dies, put a +1/+1 counter on this creature.
Legal inCommanderLegacyVintagePauper
Not legal inBrawlStandardPioneerModern