Cheapest priced copy (Judgment): $0.99 at Card Kingdom, near mint, their price list as of .
Web of Inertia 
Enchantment · Uncommon · Judgment · #53
At the beginning of combat on each opponent's turn, that player may exile a card from their graveyard. If the player doesn't, creatures they control can't attack you this turn.
Legal inCommanderLegacyVintage
Not legal inBrawlStandardPioneerModernPauper
2 printings · $0.99 to $15.99 at Card Kingdom
One ruling from Wizards of the Coast
- 1 February 2014Unless some effect explicitly says otherwise, a creature that can’t attack you can still attack a planeswalker you control.