Cheapest priced copy (Innistrad: Double Feature): $0.35 at Card Kingdom, near mint, their price list as of .
Unruly Mob 
Creature — Human · 1/1 · Common · Innistrad: Midnight Hunt · #40
Whenever another creature you control dies, put a +1/+1 counter on this creature.
Legal inCommanderPioneerModernLegacyVintagePauper
Not legal inBrawlStandard
4 printings · $0.35 to $0.49 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Innistrad: Double Feature | 40 | Common | $0.35 | $0.49 |
| Innistrad | 39 | Common | $0.35 | $0.49 |
| Innistrad: Midnight Hunt | 40 | Common | $0.35 | $0.49 |
| Shadows over Innistrad | 47 | Common | $0.35 | $0.49 |
2 rulings from Wizards of the Coast
- 8 April 2016If Unruly Mob and another creature you control die simultaneously (perhaps because they were both attacking or blocking), Unruly Mob won't be on the battlefield as its triggered ability resolves. It can't be saved by the +1/+1 counter that would have been put on it.
- 24 September 2021If Unruly Mob and another creature you control die simultaneously (perhaps because they were both attacking or blocking), Unruly Mob won't be on the battlefield as its triggered ability resolves. It can't be saved by the +1/+1 counter that would have been put on it.