Cheapest priced copy (Core Set 2020): $0.99 at Card Kingdom, near mint, their price list as of .
Rule of Law 
Enchantment · Uncommon · Core Set 2020 · #35
Each player can't cast more than one spell each turn.
Legal inCommanderPioneerModernLegacyVintage
Not legal inBrawlStandardPauper
4 printings · $0.99 to $13.99 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Tenth Edition | 37 | Uncommon | $1.29 | $6.99 |
| Core Set 2020 | 35 | Uncommon | $0.99 | $3.99 |
| Mirrodin | 19 | Rare | $1.29 | $13.99 |
| Secret Lair Drop | 2478 | Rare | $4.99 | $9.99 |
2 rulings from Wizards of the Coast
- 12 July 2019Rule of Law looks at the entire turn to see if a player has cast a spell, even if Rule of Law wasn’t on the battlefield when that spell was cast. Notably, you can’t cast Rule of Law and then cast another spell during the same turn.
- 12 July 2019If you cast a spell that was countered, you can’t cast another spell during the same turn.