Build me a Flutter app for Android and iOS

I'd like to have an app developed that shows people what they would look like with different hairstyles and hair colors. The app will process photos taken from the phone camera and all photo processing will be done using my existing REST API and machine learning solution. I will provide documentation on how to use the API and will work with you to get your code to interface with it.

The app will basically be a hair editor with categories of things to change like "Longer / Shorter", "Bangs / No Bangs", "Straight / Curly", "Blonde Color", and the level of edit that they want to apply.

I would like to include ads and in-app purchases or subscriptions. Such as paying to unlock new edits such as specific hairstyles.

I would also like to collect user data such as names, emails, demographics, etc... So either uses registration or log on with a service that we can get this information from.

I've attached an audio voice-over for an advertisement for this app, and I also attached a collection of photos of real photos of edited hair using my API.

Please let me know how you would approach this project, any questions you have for me, and a ballpark estimate of what the total project should cost.

Best Regards,
Jeremy Edmonds
HairTech Labs