I need android app developer (full stack)

I'm looking for a full stack mobile app developer (Android) for my current project. So it is essentially an app that enables people to post tasks they needed done, and also on the other side, is for people to earn extra money by doing tasks listed in the app. SAMPLE CASE: - So for example, Person A set a task “shop at xx shop for me, here’s the list” the total budget for the task is $100. - Then Person B, want to earn more money, so he goes to the app and browse some tasks. After a while, Person B found a task (or more than one task) that he likes so he makes an offer in the tasks - After a while, Person A receives notifications that people are making offers in her task (including Person B), then she go back into the app and look at the offers. Person B made a $100 offer (as given in the task by Person A), some other people make a smaller offer because they’re just starting on the app so they got no good reviews yet. Some other people been in the app for quite some time and got great reviews and good completion rate, so they are making $110+ offers. - Then Person A picked Person B for the job. - Person A then make a payment by purchasing our virtual product with the final amount of the task. - Person B will then do the job manually (offline) while communicating with Person A through the app (they could only communicate via chat and call through the app AFTER the task is accepted, which is private communication. When the task is not yet accepted, they could communicate publicly through comments on the task) - When the task is completed, Person B and A would mark ‘task completed’ in the task area. Admin will get notified when any of the ’task completed’ button is ticked. A PERSON THAT POST THE TASK - a person could post a task in the app (each task could be categorised, i.e. photography), and then this can be seen with the people that search tasks in the app. - The person that sets the task will set a budget for the task. - One task could get multiple offers from different people. - Will get app, email (and optionally text message) notifications when major activities are in place, such as, someone made an offer, offer accepted, offer completed - they will have a profile with reviews and past posts A PERSON THAT WANT TO DO THE TASK - a person could search tasks from “browse tasks” and also from task categories - once a person found a task they like, they could make a lower/higher offer on the task - they will have a profile with reviews and past tasks completion, as well as ID check There will also be referral system where user could refer their friends and earn money in the form of our virtual products. They could also track how many of their friends joined and post the task (which is when they earn their money). User could also receive and use coupon codes to get discounts of the total task price. After everything, each party will rate each other's experience through 1-5 star review. Would love to hear a quote and how long the development will take. The app visual designs will be provided. Thanks