Search Monitor Site

I want to create a simple site that will allow a user to sign up and pay (using paypal ipn) 1.00 for the access to monitor our database for 5 items for the term of 30 days. For admin side of thing, just a simple, user add/modify/delete and mass email For user side, the user signs up, they get access and have access to monitor and be emailed when something hits our database. Once they put an item in, they cant change it until either their 30 day is up OR it is found. If it is found, the site should send a simple email stating their item was found and a link (from our db) It should also link back to our site so they can modify their search terms. I would like a front page, members page, about page, FAQ page and admin page (only accessible to admin obviously) You also need to write the monitor code in php so that it will not send duplicate data to the same person. This is fairly easy and I can assist with this. The monitor job will be run as a cron job.