Cheapest priced copy (Commander Masters): $0.35 at Card Kingdom, near mint, their price list as of .
Crawling Infestation 
Enchantment · Uncommon · Innistrad: Crimson Vow · #193
At the beginning of your upkeep, you may mill two cards. (You may put the top two cards of your library into your graveyard.)
Whenever one or more creature cards are put into your graveyard from anywhere during your turn, create a 1/1 green Insect creature token. This ability triggers only once each turn.
Legal inCommanderPioneerModernLegacyVintagePauper
Not legal inBrawlStandard
3 printings · $0.35 to $3.99 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Commander Masters | 281 | Common | $0.35 | $0.49 |
| Innistrad: Double Feature | 460 | Uncommon | $0.69 | $3.99 |
| Innistrad: Crimson Vow | 193 | Uncommon | $0.39 | $0.49 |
One ruling from Wizards of the Coast
- 19 November 2021Crawling Infestation must be on the battlefield for its ability to trigger. If it's destroyed at the same time as one or more creatures you own, its ability won't trigger.