Cheapest priced copy (Dark Ascension): $0.35 at Card Kingdom, near mint, their price list as of .
Erdwal Ripper 
Creature — Vampire · 2/1 · Common · Dark Ascension · #86
Haste
Whenever this creature deals combat damage to a player, put a +1/+1 counter on it.
Legal inCommanderModernLegacyVintagePauper
Not legal inBrawlStandardPioneer
1 printing · $0.35 to $0.49 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Dark Ascension | 86 | Common | $0.35 | $0.49 |
2 rulings from Wizards of the Coast
- 22 January 2011If this creature deals combat damage to multiple players simultaneously, perhaps because some combat damage was redirected, its ability will trigger for each of those players.
- 22 January 2011The +1/+1 counter isn’t put on the creature in time to increase the amount of combat damage dealt during that combat step.