Cheapest priced copy (Modern Horizons 2): $64.99 at Card Kingdom, near mint, their price list as of .
Esper Sentinel 
Artifact Creature — Human Soldier · 1/1 · Rare · The List · #MH2-12
Whenever an opponent casts their first noncreature spell each turn, draw a card unless that player pays {X}, where X is this creature's power.
Legal inCommanderModernLegacyVintage
Not legal inBrawlStandardPioneerPauper
6 printings · $64.99 to $119.99 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Modern Horizons 2 Timeshifts | 2 | Rare | $79.99 | $119.99 |
| Modern Horizons 2 | 12 | Rare | $64.99 | $109.99 |
| Modern Horizons 2 | 328 | Rare | $74.99 | $109.99 |
| The List | MH2-12 | Rare | $74.99 | — |
| Modern Horizons 2 Promos | 12s | Rare | — | $119.99 |
| Secret Lair Drop | 2123 | Rare | — | — |
3 rulings from Wizards of the Coast
- 18 June 2021This ability checks Esper Sentinel's power when it resolves, not when the ability goes on the stack. If Esper Sentinel is no longer on the battlefield when it resolves, use the power it had the last time it was on the battlefield.
- 18 June 2021If a noncreature spell was already cast by an opponent the turn Esper Sentinel enters the battlefield, that opponent already cast their first noncreature spell this turn, and Esper Sentinel's ability won't trigger for that opponent that turn.
- 18 June 2021If Esper Sentinel's has negative power when this ability resolves, then {X} is {0}. The opponent may still choose not to pay the cost if they want you to draw a card.