Smart Bidding chased free signups for 11 months — an estimated $180K spent

The situation

A project management SaaS had been running Google Ads for 11 months. Monthly spend: $22K. They had 800 signups per month and were happy. Revenue growth was flat. The growth team couldn't understand why so many signups weren't converting to paid.

The problem

Google Ads was optimizing for "Sign Up" as the primary conversion — a free event requiring only an email address. The actual revenue event (Subscribe — $49/month) had never been configured as a conversion action. Smart Bidding had 11 months of data teaching it to find people who create free accounts and never upgrade. That's exactly what it delivered.

What we did

1. Implemented subscription_started as a GA4 event fired server-side on first successful charge via Stripe webhook
2. Created a new Google Ads conversion action importing subscription events from GA4 with a conversion value of $588 (12-month LTV)
3. Set Sign Up as a secondary (non-bidding) conversion action for funnel visibility only
4. Switched Smart Bidding to Target ROAS of 300% based on $588 LTV value — gave 4-week learning period

Why it worked

This is the most common SaaS Google Ads mistake. Free signup is not a revenue event — it's a step toward revenue. When you optimize for signups, Google finds email address creators. When you optimize for paid conversions with LTV values, Google finds buyers. The switch is simple but requires patience for the learning period.