Cheapest priced copy (Modern Horizons): $0.49 at Card Kingdom, near mint, their price list as of .
Dead of Winter 
Sorcery · Rare · Modern Horizons · #85
All nonsnow creatures get -X/-X until end of turn, where X is the number of snow permanents you control.
Legal inCommanderModernLegacyVintage
Not legal inBrawlStandardPioneerPauper
1 printing · $0.49 to $1.49 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Modern Horizons | 85 | Rare | $0.49 | $1.49 |
2 rulings from Wizards of the Coast
- 14 June 2019Dead of Winter affects only creatures that aren’t snow creatures at the time it resolves. Creatures that enter the battlefield later in the turn won’t get -X/-X.
- 14 June 2019The value of X is determined only as Dead of Winter begins to resolve. It won’t change later in the turn if the number of snow permanents you control changes.