Question: Developing a mobile app

I was curious about how much it would cost to create a mobile app that has a search engine allowing for looking up nutritional values of main fast food restaurants, various store bought food items, and big chain high end restaurants. It’s for a point system diet I am designing. For example: I am asked to join coworkers for lunch at Carl’s Jr. and need to search points on the items they provide that fit my point quota for my days diet. I want an app that searches a wide variety of food items based on a graded point system that I designed. Any thoughts?