Cheapest priced copy (Duskmourn: House of Horror Commander): $0.49 at Card Kingdom, near mint, their price list as of .
Starfield Mystic 
Creature — Human Cleric · 2/2 · Rare · Commander Masters · #839
Enchantment spells you cast cost {1} less to cast.
Whenever an enchantment you control is put into a graveyard from the battlefield, put a +1/+1 counter on this creature.
Legal inCommanderPioneerModernLegacyVintage
Not legal inBrawlStandardPauper
8 printings · $0.49 to $4.49 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Commander Masters | 839 | Rare | $0.59 | — |
| Duskmourn: House of Horror Commander | 105 | Rare | $0.49 | — |
| Foundations Jumpstart | 260 | Rare | $0.59 | — |
| Core Set 2020 | 39 | Rare | $0.59 | $4.49 |
| Core Set 2020 Promos | 39p | Rare | $0.69 | $3.49 |
| Core Set 2020 Promos | 39s | Rare | — | $4.49 |
| Secrets of Strixhaven Commander | 177 | Rare | $0.59 | — |
| Wilds of Eldraine Commander | 76 | Rare | $0.59 | — |
One ruling from Wizards of the Coast
- 12 July 2019If you cast an Aura spell targeting an opponent's permanent, you still control the Aura after it resolves.