Summary
CPA (cost-per-action) is the recommended bidding solution for driving cost-effective in-app purchases from existing app users. It bids against the purchase event itself rather than views or impressions, so spend follows users most likely to buy. Target CPM, tCPV and Active View viewability all optimise for delivery or attention and do not fit a purchase objective.
Nitin Batra is a Google Video Ads certified professional who plans and manages Demand Gen and app campaigns with conversion-based bidding across Firebase and third-party attribution setups.
Last updated: August 23, 2026
For driving cost-effective in-app purchases from existing app users in a Demand Gen campaign, the recommended bidding solution is CPA (cost-per-action), which optimises spend towards the actual purchase conversion rather than views or impressions.
- CPA (cost-per-action)
- Target CPM
- tCPV (cost-per-view)
- Viewability with Active View
The correct answer is: CPA (cost-per-action)
Key Takeaways
- – CPA (cost-per-action) is the recommended bidding solution when a Demand Gen advertiser wants cost-effective in-app purchases from existing app users.
- – CPA bidding only works properly once the in-app purchase conversion is importing into Google Ads from Firebase, Google Analytics or an app attribution partner, and is set as a primary account-default goal.
- – Bid strategy should always match the objective: awareness objectives use CPM or CPV style bidding, while revenue and action objectives need conversion bidding.
- – A common mistake is setting a target CPA far below historical cost per purchase, which starves delivery and leaves the campaign under-serving instead of learning.
Why is CPA better than tCPV for driving in-app purchases?
tCPV optimises for views at a target cost per view, so it buys attention, not outcomes. A user can watch the full ad and never open the app. CPA bidding evaluates each impression on the probability of the purchase event firing, so your budget flows to users likely to spend inside the app.
How do I import in-app purchase conversions into Google Ads for Demand Gen bidding?
Link Firebase or your Google Analytics 4 property to Google Ads, or connect a certified app attribution partner such as AppsFlyer or Adjust. Then go to Goals, Conversions, Summary, click New conversion action and select App, choosing the in-app purchase event. Mark it as a primary action so it is included in Conversions bidding.
Does CPA bidding need a minimum volume of conversions before it performs well?
Yes. Conversion bidding learns from historical data, and thin conversion volume gives the system very little to work with. Most practitioners want a steady flow of app purchase conversions per week before tightening the target CPA. If volume is low, start with a target closer to your current cost per purchase and reduce it in steps of ten to fifteen percent.
Can I use CPA bidding with a remarketing audience of existing app users?
Yes, and that is exactly the setup this question describes. Build the audience from your app user lists, Firebase audiences or Customer Match data, add it in the Audiences section of the Demand Gen ad group, and run Conversions bidding with a target CPA. The audience narrows who sees the ad and the bid strategy controls what you pay for the purchase.