Cheapest priced copy (The Lost Caverns of Ixalan): $0.35 at Card Kingdom, near mint, their price list as of .
Sage of Days 
Creature — Human Wizard · 3/2 · Common · The Lost Caverns of Ixalan · #73
When this creature enters, look at the top three cards of your library. You may put one of those cards back on top of your library. Put the rest into your graveyard.
Legal inCommanderBrawlStandardPioneerModernLegacyVintagePauper
1 printing · $0.35 to $0.49 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| The Lost Caverns of Ixalan | 73 | Common | $0.35 | $0.49 |