React Native app

With your help we want to Develop our App "equable" further. Our product is currently a Nature sound App with medical knowledge Reference. For the Future we want to Develop it into an innovative Sleep and Relaxation Application, science based. We have programmed our App until now with the help of our full stack developer in our founding Team. We used react native For our Code. Now we want some extern Support. Concretely we want you to implement a subscription based payment system. The subscription should unlock a full Version. Regarding to payment system no Backend Like Databanks or a Profile is implemented yet. Payment should Work Like in the App "Calm". You can find our App at Playstore and Applestore. https://play.google.com/store/apps/details?id=com.equable.sleep https://apps.apple.com/de/app/equable/id1633138847?l=en If you could imagine working with us, we would be happy to hear from you. Is it already possible for you to estimate the price for our demand?