Create PHP pages, interact with MySQL and PayPal IPN

I need a section of a website to be completed. It will work within an existing Joomla site but will be it's own PHP using MySQL Database and PayPal IPN with subscriptions. The initial page will be a signup page, it will require customer to enter name, address, etc. and will have 4 subscription levels to choose from with different pricing within a dropdown. When they click submit, it will add them to a database that is already existing. It will mark them as inactive. Then they will go to a 2nd page that will be a "confirmation" page that will list all details and a button to click that directs to PayPal IPN. Once finished with payment, they will need to direct to a thank you page with additional information, on that page or within the PHP it will mark their account active in the database. There will be a followup project to this that will have a customer signin page based on above information that will direct them to their "own" site with database information specifically for them. Please don't just list a bunch of sites that you've done, instead, let me know thoughts, questions, etc.