PHP Point Of Sale customization

Project Description The goal of the project is customization of the existing Point of Sale system originally intended to work in retail business in order to reflect the specifics of sport club accounting. Following major changes are required. - System shall be able to keep records of not only sales , but also visits. - System shall be able to register subscriptions and visits done on this subscription - Customization of system data model in parts of Customer Account, Sales and Items as well as gift cards. The project is done on several phases based on detailed requirements prioritization. Each phase is started after completion and acceptance of previous one, but time and price estimation is required for each phase of envisioned project. Detailed requirements with phases breakdown are attached. Please specify your desired payment for each phase.