Cheapest priced copy (Avacyn Restored): $0.49 at Card Kingdom, near mint, their price list as of .
Lone Revenant 
Creature — Spirit · 4/4 · Rare · Commander 2015 · #96
Hexproof (This creature can't be the target of spells or abilities your opponents control.)
Whenever this creature deals combat damage to a player, if you control no other creatures, look at the top four cards of your library. Put one of them into your hand and the rest on the bottom of your library in any order.
Legal inCommanderModernLegacyVintage
Not legal inBrawlStandardPioneerPauper
2 printings · $0.49 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Avacyn Restored | 64 | Rare | $0.49 | $0.49 |
| Commander 2015 | 96 | Rare | $0.49 | — |
4 rulings from Wizards of the Coast
- 1 May 2012If you control no creatures when Lone Revenant’s ability resolves, you’ll still look at the top four cards and put one into your hand.
- 1 May 2012If you control Lone Revenant and any other creature (including another Lone Revenant), its ability won’t trigger.
- 1 May 2012Check whether Lone Revenant’s ability triggers after combat damage is dealt but before any creatures that are destroyed due to combat damage leave the battlefield. For example, if you control Lone Revenant and another creature, and that other creature takes lethal damage in the same combat damage step that Lone Revenant deals damage to a player, Lone Revenant’s ability won’t trigger.
- 1 May 2012You must put one of the cards into your hand, even if you’d rather put all four on the bottom of your library.