Cheapest priced copy (Innistrad: Double Feature): $0.35 at Card Kingdom, near mint, their price list as of .
Sigardian Paladin 
Creature — Human Knight · 4/4 · Uncommon · Innistrad: Double Feature · #514
As long as you've put one or more +1/+1 counters on a creature this turn, this creature has trample and lifelink.
{1}{G}{W}: Target creature you control with a +1/+1 counter on it gains trample and lifelink until end of turn.
Legal inCommanderPioneerModernLegacyVintage
Not legal inBrawlStandardPauper
2 printings · $0.35 to $0.49 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Innistrad: Double Feature | 514 | Uncommon | $0.35 | $0.49 |
| Innistrad: Crimson Vow | 247 | Uncommon | $0.35 | $0.49 |
2 rulings from Wizards of the Coast
- 19 November 2021Sigardian Paladin's first ability applies as long as you put a +1/+1 counter on a permanent this turn and that permanent was a creature at the time you put the counter on. It doesn't matter if that creature later left the battlefield, lost its counters, or somehow stopped being a creature.
- 19 November 2021Sigardian Paladin's last ability can target only a creature with a +1/+1 counter on it. Once that ability has resolved, the creature has trample and lifelink until end of turn even if it somehow loses its counters or stops being a creature (although trample doesn't help a noncreature permanent much).