Cheapest priced copy (Legends): $2.29 at Card Kingdom, near mint, their price list as of .
Equinox 
Enchantment — Aura · Common · Legends · #13
Enchant land
Enchanted land has "{T}: Counter target spell if it would destroy a land you control."
Legal inCommanderLegacyVintagePauper
Not legal inBrawlStandardPioneerModern
1 printing · $2.29 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Legends | 13 | Common | $2.29 | — |
7 rulings from Wizards of the Coast
- 4 October 2004Equinox will not counter a spell that has a random chance of destroying a land.
- 4 October 2004Equinox will not counter a spell that deals damage to an animated land, even if it would deal more damage than the land's toughness. This is because the spell itself does not destroy the land directly. The land is destroyed by a game rule.
- 4 October 2004The ability can target any spell, even one that would not destroy a land.
- 4 October 2004Equinox will not counter a spell which would indirectly cause destruction of one of your lands.
- 4 October 2004Equinox will not counter a spell which requires sacrificing land when it enters or one that requires sacrificing land as part of the cost to cast it.
- 1 October 2008Will not counter a spell which would destroy a land only if a choice is made.
- 20 September 2013When the activated ability resolves, determine whether the targeted spell would destroy a land if it resolved right then. If it would, then counter that spell. Otherwise, it is not countered, even if the spell could, under other circumstances, destroy a land.