This is always on the mind of a company that is just getting into custom mobile app development. The truth is, there is not a way to give you defined costs for your project since every project is different. However, there are several guidelines to go by that can help you and your developer determine what the overall costs could be.
Set Clear Goals
It is important to determine what you want your app to do. Knowing what its purpose is from the start will help a project stay focused and make it easier to see if the project is achieving what you need it to achieve. For example, if your app needs to automate product sales for customers in a store, then having a barcode scanner integrated into the app can make it easier for customers to buy products. The project can focus on adding only the features that make the buying process easier for customers, which is exactly what you need it to do.
To get the best results, sit down with your team, and determine what outcomes are most important for your mobile app development project.