Cheapest priced copy (Battlebond): $0.59 at Card Kingdom, near mint, their price list as of .
Inner Demon 
Enchantment — Aura · Uncommon · Battlebond · #48
Enchant creature
Enchanted creature gets +2/+2, has flying, and is a Demon in addition to its other types.
When this Aura enters, all non-Demon creatures get -2/-2 until end of turn.
Legal inCommanderLegacyVintage
Not legal inBrawlStandardPioneerModernPauper
3 printings · $0.59 to $1.99 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Battlebond | 48 | Uncommon | $0.59 | $1.99 |
| Jumpstart 2022 | 428 | Uncommon | $0.69 | — |
| The List | BBD-48 | Uncommon | — | — |
One ruling from Wizards of the Coast
- 8 June 2018Inner Demon's triggered ability affects only non-Demon creatures on the battlefield at the time it resolves. Creatures that enter the battlefield later in the turn won't get -2/-2. Unless Inner Demon leaves the battlefield before that ability resolves, the enchanted creature won't get -2/-2.