App development for a secure, shareable gps tracking device.

Hi there. Looking for pricing on an IOS and Android friendly app that will have the capability to pair with a custom built gps device with the purpose of locating vehicles. It must have map capabilities, device pairing via QR code and the ability to share with a third party app holder with two way consent.
The app needs to be secure and user friendly.

To the right developer, a profit share agreement may be possible.

The app will be subscription based.

Thanks!
Lee