Starting from $1000 and up I develop Apps for Google and Apple App Stores. I use the Cordova framework which allows a single codebase to be compiled into both native Android .APKs and Apple .IPAs meaning you do not need to developer the same thing twice. Inexperienced develeopers and firms that want to overcharge you will often have two separate codebases doing everything twice. An Android App in JAVA and an iOS App in Swift/C.

I have my own Google and Apple Developer accounts so I understand the process your business will need to go through when opening yours such as getting a DUNS Number, managing signing keys, and the testing and release phases.