Cheapest priced copy (Wilds of Eldraine: Enchanting Tales): $0.35 at Card Kingdom, near mint, their price list as of .
Dark Tutelage 
Enchantment · Uncommon · Wilds of Eldraine: Enchanting Tales · #28
At the beginning of your upkeep, reveal the top card of your library and put that card into your hand. You lose life equal to its mana value.
Legal inCommanderModernLegacyVintage
Not legal inBrawlStandardPioneerPauper
2 printings · $0.35 to $0.79 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Magic 2011 | 90 | Rare | $0.49 | $0.79 |
| Wilds of Eldraine: Enchanting Tales | 28 | Uncommon | $0.35 | $0.49 |
3 rulings from Wizards of the Coast
- 15 August 2010The mana value of the revealed card is determined solely by the mana symbols printed in its upper right corner. The mana value is the total amount of mana in that cost, regardless of color. For example, a card with mana cost {3}{U}{U} has mana value 5.
- 15 August 2010If the mana cost of the revealed card includes {X}, X is considered to be 0.
- 15 August 2010If the revealed card has no mana symbols in its upper right corner (because it's a land card, for example), its mana value is 0.