How do you Create a Working Search Bar for products?

My app will allow users to search for every day products and instantly compare prices across different stores, helping them identify the cheapest option available. I just want to know how to make it so that it identifies the product, the cheapest possible price and in which store it is available. How will this correlate to the screens? Do I have to create screens for each product?

Never code data into your app.
Always keep it in a database somewhere.