Cheapest priced copy (Magic 2012): $0.39 at Card Kingdom, near mint, their price list as of .
Circle of Flame 
Enchantment · Uncommon · Magic 2015 · #135
Whenever a creature without flying attacks you or a planeswalker you control, this enchantment deals 1 damage to that creature.
Legal inCommanderPioneerModernLegacyVintage
Not legal inBrawlStandardPauper
3 printings · $0.39 to $2.29 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| DCI Promos | 78 | Rare | — | $2.29 |
| Magic 2012 | 127 | Uncommon | $0.39 | $0.79 |
| Magic 2015 | 135 | Uncommon | $0.39 | $0.99 |
2 rulings from Wizards of the Coast
- 18 July 2014Circle of Flame's ability triggers only if a creature without flying is declared as an attacker during the declare attackers step. If a creature with flying attacks you or a planeswalker you control and then loses flying, or if a creature without flying is put onto the battlefield attacking you or a planeswalker you control, the ability won't trigger.
- 1 February 2021Circle of Flame is banned in Pauper (not just non-legal), due to a special case on MTGO: https://magic.wizards.com/en/articles/archive/news/january-21-2019-banned-and-restricted-announcement