One of the most popular React Native package for in-app purchases is react-native-iap. It's suitable for using basic features of in-app purchases but still requires you to do the hardest work — writing a server code and receipt validation.
Keep in mind react-native-iap will provide the basic features you need but is not a turnkey solution, implementing In-app purchases in your app will still require quite some work.
Also, implementing the client side is only one side of the coin, you'll have to implement the server side to validate your receipts (which is probably the most time consuming part to do it correctly).
It may take a couple of months to implement in-app purchases for React Native. Connecting to RTDN/Apple Servers, validating receipt, storing subscription, handling server2server notification and purchases data — all these requires deploying a client and a server side code.
Both SDKs written in pure Swift/Kotlin and support iOS 9+, Android 4.1+ which fit for 99.9% users.
5 SDK methods are all you need to deploy IAPs and get subscription data from Apple and Google without coding.
It takes only a couple of hours for a junior developer to implement IAPs with Adapty React Native SDK
Make a purchase with receipt verification with a single method. Apple Promotion Offer supported right out of the box.
Restore purchases when a user re-install the app.
Link transaction to a user ID in your system.
Set any number of custom user attributes and set a separate IDs for each analytics/attribution services.
Link a user with transactions to an attribution such as ad source, campaign, ad, creative. AppsFlyer, Adjust, Branch, and Apple Seach Ads supported.