I'm trying to build an exchange website which hosts items that other people are selling. I want the site to show the prices that people are selling at but will not see their contact information until they pay a certain amount. I obviously want to make sure that the page is completely inaccessible by those who haven't paid. In addition, it would be convenient if it could also have a 30 day access period or a certain number of views for the user who has paid.
Can anyone recommend a php-based script or anything else I can use in order to make these features possible?