Mobile development

I need an Android app. I would like it designed and built. I know this is super easy to build, since you are experienced developers. This way, high offers will not be accepted. This project is to develop a simple Android app as a model/draft for a multi users different store owners. That means it will need to be ready for in the future multi vendors use it to register their products with specifications and so on. But this app will need to have functions that will make possible for it to be integrated in the future with a backend system. For now it needs registration fields for final users, where they can put their complete names, email, telephone and address and a function at the checkout that will allow users to mention if the delivery address is the same of the registration, if not, the person should inform which is. It should be ready to send email notifications of future orders statuses, but doesn't need to be now. It should be ready to receive a future function of GPS location that will allow the user to choose stores in a range of 30km. It is not now, but it should be ready for a future integration with a multi users back end website that will allow it to inform the sellers that they received orders. It should be ready to receive integrations of my country's payment methods, but the integration will not be done now. For now it can be without backend system since it is a model/draft for a future functional app. The app will need to have some fictional products appearing just for test, and the test needs to allow complete buying experience until the checkout procedure.