Cheapest priced copy (March of the Machine): $6.49 at Card Kingdom, near mint, their price list as of .
Thalia and The Gitrog Monster 
Legendary Creature — Human Frog Horror · 4/4 · Mythic · March of the Machine · #316
First strike, deathtouch
You may play an additional land on each of your turns.
Creatures and nonbasic lands your opponents control enter tapped.
Whenever Thalia and The Gitrog Monster attacks, sacrifice a creature or land, then draw a card.
Legal inCommanderPioneerModernLegacyVintage
Not legal inBrawlStandardPauper
5 printings · $6.49 to $79.99 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| March of the Machine | 255 | Mythic | $6.49 | $7.99 |
| March of the Machine | 316 | Mythic | $7.99 | $10.99 |
| March of the Machine Promos | 255p | Mythic | $7.99 | $10.99 |
| March of the Machine Promos | 255s | Mythic | — | $11.99 |
| Store Championships | 12 | Mythic | — | $79.99Out of stock |
2 rulings from Wizards of the Coast
- 14 April 2023As the last ability resolves, sacrificing a creature or land isn’t optional. If you control a creature or land (and if you control Thalia and The Gitrog Monster, you probably do), you must sacrifice one.
- 14 April 2023The effect of Thalia and The Gitrog Monster’s ability that allows you to play an additional land is cumulative with similar effects. For example, if you control Thalia and The Gitrog Monster and another permanent with that ability, you’ll be able to play three lands during each of your turns.