Indoor navigation systems help people navigate inside large buildings such as shopping malls. In this paper, a smart location-based mobile shopping application for Android devices is proposed. The flow of the application is that user searches a product, and then INOP (Indoor Navigation and Online Payment) identifies the location and searches the product inside the shopping mall. To make the navigation system, this paper proposes a Shortest Path Algorithm. To add a product to the cart, the user should scan the barcode of the product with their android phone. Once the shopping is done by the user, the user can make payment online.