Our app has a flat-based pricing model, which means that you only get charged for the plan to which you choose to upgrade. The initial plan is a free plan, and it comes with 150 free subscriptions.  If you have more than 150 subscriptions, then you will have to upgrade the plan to the next one.  We only charge a low flat fee, and we won't bill you for any percentage of the processed subscriptions.  You can see our subscription plans on our Shopify App Store listing page: https://apps.shopify.com/seal-subscriptions