Cheapest priced copy (Commander 2020): $0.35 at Card Kingdom, near mint, their price list as of .
Cavalry Pegasus 
Creature — Pegasus · 1/1 · Common · Duel Decks: Heroes vs. Monsters · #4
Flying
Whenever this creature attacks, each attacking Human gains flying until end of turn.
Legal inCommanderPioneerModernLegacyVintagePauper
Not legal inBrawlStandard
3 printings · $0.35 to $1.49 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Commander 2020 | 81 | Common | $0.35 | — |
| Duel Decks: Heroes vs. Monsters | 4 | Common | $0.35 | — |
| Theros | 2 | Common | $0.35 | $1.49 |
2 rulings from Wizards of the Coast
- 15 September 2013Once the triggered ability resolves, the attacking Humans will continue to have flying even if Cavalry Pegasus leaves the battlefield.
- 15 September 2013The attacking Humans gain flying before blockers are declared.