Flutter Developer – iOS & Android Subscription / In-App Purchase Integration

I have an existing Flutter/Firebase mobile application that is complete and being prepared for launch on the Apple App Store and Google Play Store. I need an experienced Flutter developer to implement the app's subscription/payment infrastructure on both platforms... (Budget: $10 - $30 USD, Jobs: Android, Dart, Flutter, Google Firebase, iOS, iOS Development, iPhone, Mobile App Development, Mobile Development, Payment Gateway Integration)