Cheapest priced copy (Jumpstart 2022): $0.35 at Card Kingdom, near mint, their price list as of .
Avalanche Caller 
Snow Creature — Human Wizard · 1/3 · Uncommon · Kaldheim · #45
{2}: Target snow land you control becomes a 4/4 Elemental creature with hexproof and haste until end of turn. It's still a land. (A creature with hexproof can't be the target of spells or abilities your opponents control.)
Legal inCommanderPioneerModernLegacyVintage
Not legal inBrawlStandardPauper
2 printings · $0.35 to $0.49 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Jumpstart 2022 | 274 | Uncommon | $0.35 | — |
| Kaldheim | 45 | Uncommon | $0.35 | $0.49 |
8 rulings from Wizards of the Coast
- 5 February 2021The {S} symbol is a generic mana symbol. It represents a cost that can be paid by one mana that was produced by a snow source. That mana can be any color or colorless.
- 5 February 2021Snow isn’t a type of mana. If an effect says you may spend mana as though it were any type, you can’t pay for {S} using mana that wasn’t produced by a snow source.
- 5 February 2021In most cases, the land that becomes a creature will remain colorless. If another effect caused the land to have one or more colors, the resulting creature land will retain those colors.
- 5 February 2021A land that becomes a creature because of Avalanche Caller’s activated ability will retain any other supertypes, card types, subtypes, and abilities it had. In particular, it will be a snow creature land.
- 5 February 2021Some cards have additional effects for each {S} spent to cast them. You can cast these spells even if you don’t spend any snow mana to cast them; their additional effects simply won’t do anything.
- 5 February 2021The Kaldheim set doesn’t have any cards with mana costs that include {S}, but some previous sets do. If an effect says such a spell costs {1} less to cast, that reduction doesn’t apply to any {S} costs. This is also true for activated abilities that include {S} in their activation costs and effects that reduce those costs.
- 5 February 2021The activated ability doesn’t cause the target snow land to become tapped or untapped.
- 5 February 2021Snow is a supertype, not a card type. It has no rules meaning or function by itself, but spells and abilities may refer to it.