The honest answer is: it depends on scope — but you can still plan with real numbers. A simple app with a handful of screens, a contact or booking form and no user accounts typically starts in the low four figures. Add user logins, payments, a backend with an admin panel, and multi-language support, and the figure grows in predictable steps.
The three biggest cost drivers are: (1) whether you need a custom backend and admin dashboard, (2) how many distinct screens and flows the app has, and (3) integrations — payments, maps, push notifications, third-party APIs. Design complexity matters too, but less than people expect.
At Codrex we quote apps individually after a short call, but our project calculator gives you an instant range so you can budget before you talk to anyone. Cross-platform frameworks like Flutter let us build for iOS and Android at once, which keeps costs down for most business apps.
One tip: launch with a focused first version. It is cheaper, faster to the store, and you learn what users actually want before investing in the long tail of features.