MP3 Mobile App

Hey coders! I'm looking to create a very simple Android app that has 4-5 options. 1. Play 1-50 short mp3 files randomly from a server online or through the app, doesn't matter. 2. Option to choose a category and play 1-50 from that directory on the server or through the app. 3. Option to purchase more another 50 files to listen to and open the purchased directory to the user to be able to listen to another 50 files). 4. Option to record himself on his phone and add this to the database of files for others to listen to. There are more things that I'd like to discuss but that's the basic app that I want to get done first. You must be able to keep working with me on improving this app long-term. Please place your bid only if you're serious, quick, and motivated to get this app done on the best way possible. Thanks, Mike