Cheapest priced copy (Marvel Universe): $1.49 at Card Kingdom, near mint, their price list as of .
Concerted Effort 
Enchantment · Rare · Ravnica: City of Guilds · #8
At the beginning of each upkeep, creatures you control gain flying until end of turn if a creature you control has flying. The same is true for fear, first strike, double strike, landwalk, protection, trample, and vigilance.
Legal inCommanderModernLegacyVintage
Not legal inBrawlStandardPioneerPauper
3 printings · $1.49 to $10.99 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Marvel Universe | 42 | Mythic | $1.49 | $1.99 |
| Ravnica: City of Guilds | 8 | Rare | $3.49 | $10.99 |
| Star Trek Commander | 420 | Rare | — | — |
3 rulings from Wizards of the Coast
- 1 October 2005For example, a player controls three creatures when Concerted Effort’s ability resolves: one creature with flying and protection from red, one with islandwalk and protection from green; and one with vigilance. All three creatures will have flying, islandwalk, vigilance, protection from red, and protection from green until the end of the turn.
- 1 October 2005Creatures keep all abilities granted this way until the end of the turn, even if Concerted Effort or the original creature with that ability leaves the battlefield.
- 1 May 2006In Two-Headed Giant, triggers only once per upkeep, not once for each player.