Cheapest priced copy (Commander 2019): $2.49 at Card Kingdom, near mint, their price list as of .
Jace's Sanctum 
Enchantment · Rare · Magic Origins · #61
Instant and sorcery spells you cast cost {1} less to cast.
Whenever you cast an instant or sorcery spell, scry 1.
Legal inCommanderPioneerModernLegacyVintage
Not legal inBrawlStandardPauper
3 printings · $2.49 to $4.99 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Commander 2019 | 88 | Rare | $2.49 | — |
| Magic Origins | 61 | Rare | $2.79 | $4.49 |
| Magic Origins Promos | 61p | Rare | $3.99 | $4.99 |
4 rulings from Wizards of the Coast
- 22 June 2015The first ability of Jace’s Sanctum can’t reduce the colored mana requirement of an instant or sorcery spell.
- 22 June 2015Jace’s Sanctum’s scry ability will resolve before the instant or sorcery spell that caused it to trigger.
- 22 June 2015If there are additional costs to cast an instant or sorcery spell, apply those before applying cost reductions.
- 22 June 2015Jace’s Sanctum can reduce alternative costs such as miracle or overload costs.