Cheapest priced copy (Dominaria Remastered): $0.35 at Card Kingdom, near mint, their price list as of .
Krosan Restorer 
Creature — Human Druid · 1/2 · Common · Torment · #130
{T}: Untap target land.
Threshold — {T}: Untap up to three target lands. Activate only if there are seven or more cards in your graveyard.
Legal inCommanderLegacyVintagePauper
Not legal inBrawlStandardPioneerModern
2 printings · $0.35 to $12.99 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Dominaria Remastered | 168 | Common | $0.35 | $0.49 |
| Torment | 130 | Common | $0.35 | $12.99 |
One ruling from Wizards of the Coast
- 8 December 2022Krosan Restorer’s activated abilities aren’t mana abilities. They each use the stack and can be responded to. Notably, they can’t be activated while you’re casting a spell or activating another ability. If you want to use Krosan Restorer to add enough mana to pay for a spell or ability, you may tap land(s) you control, untap them with Krosan Restorer, and tap the lands again all before you start casting a spell or activating an ability.