Cheapest priced copy (Rise of the Eldrazi): $0.35 at Card Kingdom, near mint, their price list as of .
Demonic Appetite 
Enchantment — Aura · Common · Rise of the Eldrazi · #106
Enchant creature you control
Enchanted creature gets +3/+3.
At the beginning of your upkeep, sacrifice a creature.
Legal inCommanderModernLegacyVintagePauper
Not legal inBrawlStandardPioneer
1 printing · $0.35 to $0.79 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Rise of the Eldrazi | 106 | Common | $0.35 | $0.79 |
2 rulings from Wizards of the Coast
- 15 June 2010If another player gains control of either Demonic Appetite or the enchanted creature (but not both), Demonic Appetite will be enchanting an illegal permanent. The Aura will be put into its owner’s graveyard as a state-based action.
- 15 June 2010When Demonic Appetite’s triggered ability resolves, you may sacrifice the creature enchanted by Demonic Appetite. If you control no other creatures, you’ll have to sacrifice that one.