Cheapest priced copy (Magic Origins): $0.35 at Card Kingdom, near mint, their price list as of .
Call of the Full Moon 
Enchantment — Aura · Uncommon · Magic Origins · #134
Enchant creature
Enchanted creature gets +3/+2 and has trample. (It can deal excess combat damage to the player or planeswalker it's attacking.)
At the beginning of each upkeep, if a player cast two or more spells last turn, sacrifice this Aura.
Legal inCommanderPioneerModernLegacyVintage
Not legal inBrawlStandardPauper
1 printing · $0.35 to $0.49 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Magic Origins | 134 | Uncommon | $0.35 | $0.49 |
2 rulings from Wizards of the Coast
- 22 June 2015Call of the Full Moon's last ability will look at the entire previous turn, even if Call of the Moon wasn't on the battlefield for some or all of that turn. For example, if you cast Call of the Full Moon and another spell on the same turn, you'll have to sacrifice Call of the Full Moon at the beginning of the upkeep of the following turn.
- 22 June 2015A single player must have cast two or more spells during the previous turn for Call of the Full Moon's last ability to trigger. If multiple players each cast just one spell during that turn, the ability won't trigger.