Why app development quotes vary so much
Two things affect almost every app quote: how much the app needs to do, and how the developer charges. A tool with one workflow and an admin screen is a much smaller job than a platform with many customer accounts, billing, and integrations. The billing method also matters, because hourly billing is often what makes projects run over budget.
With hourly billing, the developer earns more when a project takes longer. With a fixed price, our goal is the same as yours: deliver what we agreed, on time.