Cheapest priced copy (The Lost Caverns of Ixalan Commander): $1.99 at Card Kingdom, near mint, their price list as of .
Pact of the Serpent 
Sorcery · Rare · The Lost Caverns of Ixalan Commander · #206
Choose a creature type. Target player draws X cards and loses X life, where X is the number of creatures they control of the chosen type.
Legal inCommanderLegacyVintage
Not legal inBrawlStandardPioneerModernPauper
2 printings · $1.99 to $2.29 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Kaldheim Commander | 9 | Rare | $2.29 | — |
| The Lost Caverns of Ixalan Commander | 206 | Rare | $1.99 | — |
3 rulings from Wizards of the Coast
- 5 February 2021You choose the target player as you cast Pact of the Serpent, but you don't choose the creature type until the spell resolves.
- 5 February 2021You must choose an existing creature type, such as Squirrel or Knight. You can't choose card types (e.g., artifact) or supertypes (e.g., snow).
- 5 February 2021The value of X is based on the number of creatures the player controls of the chosen type as Pact of the Serpent resolves.