Cheapest priced copy (Duel Decks: Phyrexia vs. the Coalition): $0.35 at Card Kingdom, near mint, their price list as of .
Phyrexian Battleflies 
Creature — Phyrexian Insect · 0/1 · Common · The List · #INV-114
Flying
{B}: This creature gets +1/+0 until end of turn. Activate no more than twice each turn.
Legal inCommanderLegacyVintagePauper
Not legal inBrawlStandardPioneerModern
3 printings · $0.35 to $2.99 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Duel Decks: Phyrexia vs. the Coalition | 3 | Common | $0.35 | — |
| Invasion | 114 | Common | $0.35 | $2.99 |
| The List | INV-114 | Common | $0.35 | — |