“all we did was mapping their trial event to trial and their cost per purchase/ the actual cost per trial went down by I think around 35% only with that change same creatives same campaigns just different event optimization”

Remapping trial event from purchase to trial cut CAC 35% — same creatives, same campaigns

One app with a high CAC was optimizing Meta toward purchase events — competing in an auction against e-commerce advertisers willing to pay $200 CPP for a conversion worth only $10–15 to the app. Simply remapping the optimization signal to trial start, with zero creative or campaign changes, dropped cost per trial by 35%. The mechanism: matching your bid signal to what you actually want lowers CPMs from irrelevant high-bidders.