Cheapest priced copy (Oath of the Gatewatch): $0.49 at Card Kingdom, near mint, their price list as of .
Hedron Alignment 
Enchantment · Rare · Oath of the Gatewatch · #57
Hexproof
At the beginning of your upkeep, you may reveal your hand. If you do, you win the game if you own a card named Hedron Alignment in exile, in your hand, in your graveyard, and on the battlefield.
{1}{U}: Scry 1.
Legal inCommanderPioneerModernLegacyVintage
Not legal inBrawlStandardPauper
2 printings · $0.49 to $1.29 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Oath of the Gatewatch | 57 | Rare | $0.49 | $0.79 |
| Oath of the Gatewatch Promos | 57s | Rare | — | $1.29 |
One ruling from Wizards of the Coast
- 22 January 2016The Hedron Alignment in exile must be face up. If it’s face down, it won’t count, even if you are allowed to look at it.