Hi Max,
That question is a bit like "How Long Is A Piece Of String"
It really depends on your audience I guess.
Is it a bespoke app to the specifications of a single Customer?
Or is it intended to be a SaaS app that you intend (hope) to subscribe to many users?
We have many many apps. Some of the bespoke applications that are custom developed run into 6 figures.
Others we sell as a subscription... ie $10 per Active Employee per month.
So, it really all depends.