Cheapest priced copy (Dragons of Tarkir): $0.35 at Card Kingdom, near mint, their price list as of .
Magmatic Chasm 
Sorcery · Common · Shadows over Innistrad · #172
Creatures without flying can't block this turn.
Legal inCommanderPioneerModernLegacyVintagePauper
Not legal inBrawlStandard
2 printings · $0.35 to $0.49 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Dragons of Tarkir | 148 | Common | $0.35 | $0.49 |
| Shadows over Innistrad | 172 | Common | $0.35 | $0.49 |
One ruling from Wizards of the Coast
- 8 April 2016Because Magmatic Chasm’s effect doesn’t change the characteristics of any permanents, the set of creatures affected by Magmatic Chasm is constantly updated. Creatures without flying that enter the battlefield later in the turn won’t be able to block.