If you’re using a development store, the app is free until you upgrade the store to a paid Shopify store plan.
To continue, you’ll need to select a plan and click “Approve” on the next page. Don’t worry, this is just a test charge. The payment screen will confirm that “You will not be billed for this test charge.”
After upgrading to a paid Shopify store plan, please go to the app’s Plans section and approve the subscription to keep access to all premium features.