It mainly depends upon the functionality, features you require in the app. Additionally, the location, size of the firms you are giving the project matters.
Being in outsourcing business, we are often asked «how much will my project cost». And often we any details of the project. Of course, at this point we cannot come up with an estimate.
As mentioned above, an app development cost will depend on such factor as functionality, the number of platforms, complexity level and so on. That is, an app may have just some basic features. Alternatively, it may have an advanced AI algorithm embedded. For these two options, the budgets would be completely different.