Cheapest priced copy (Conflux): $0.99 at Card Kingdom, near mint, their price list as of .
Lapse of Certainty 
Instant · Common · Conflux · #9
Counter target spell. If that spell is countered this way, put it on top of its owner's library instead of into that player's graveyard.
Legal inCommanderModernLegacyVintagePauper
Not legal inBrawlStandardPioneer