"ConnectSphere": A Simple Android Messaging/Calling App

I'm looking to build a simple, user-friendly, Android-only messaging and calling app called "ConnectSphere". Key features of this app will include:

- Fast text messaging
- Clear voice calls
- Group chats
- Multimedia sharing
- Basic encryption for user security
- Free for users, with absolutely no ads.

I'm on a tight budget of USD 100. Here are a few questions for you:

1. How much would it cost for a basic version?
2. How long will it take to develop?
3. Do you have similar projects in your portfolio that you can showcase?

The app will require phone number verification for user authentication. I am not looking for overly complicated features, just a solid, reliable app that can cater to text messaging, group chats and multimedia sharing. Skills and experience in Android app development, real-time messaging systems, and basic encryption methods will be beneficial for this project. Looking forward to your responses.