Database and implementation

Looking for a database to be built for users to input information and receive information based on the best deal. 8-9 categories of information. The user will input 2 from a list (category 1 will have multiple selections), and two check boxes. The database will need to compute the highest outcome based on the input from the user. It will also need to output the outcome and how it got there. Integration of referral links for the output will be needed. Also it will need a user registration with guest and member use. I would like this to be setup for later integration of an iphone application. Also, later integration of database updates from external websites. These will be further upgrades and will just need access for later.