Cheapest priced copy (Commander 2015): $0.99 at Card Kingdom, near mint, their price list as of .
Sigil of the Empty Throne 
Enchantment · Rare · Magic Origins · #31
Whenever you cast an enchantment spell, create a 4/4 white Angel creature token with flying.
Legal inCommanderPioneerModernLegacyVintage
Not legal inBrawlStandardPauper
10 printings · $0.99 to $11.99 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Commander 2015 | 80 | Rare | $0.99 | — |
| Commander 2018 | 74 | Rare | $1.29 | — |
| Commander Masters | 836 | Rare | $0.99 | — |
| Conflux | 18 | Rare | $1.29 | $5.99 |
| Duskmourn: House of Horror Commander | 103 | Rare | $0.99 | — |
| Jumpstart 2022 | 244 | Rare | $1.29 | — |
| Magic Origins | 31 | Rare | $1.29 | $4.99 |
| Planechase 2012 | 11 | Rare | $1.29 | — |
| Planechase Anthology | 11 | Rare | $0.99 | — |
| Time Spiral Remastered | 301 | Special | $0.99 | $11.99 |
2 rulings from Wizards of the Coast
- 19 March 2021An ability that triggers when a player casts a spell resolves before the spell that caused it to trigger, but after targets have been chosen for that spell. It resolves even if that spell is countered.
- 19 March 2021Because it's not on the battlefield yet, casting Sigil of the Empty Throne won't cause its own ability to trigger.