This would be the classical buyer - seller website, with the intermediary (me, owning the website) would get a cut.
Basically, the site would need to integrate the following:
- user creation (both types);
- form creation by the first category of users (who pay);
- form interaction by the second category of users (who get paid);
- complex payment and comission system;
- secure payments;
- adequate reports for both types of users;
- adequate reports for me (for accounting purposes).
I should have complete control over the website. Domain name and data center hosting is not an issue. The website should be able to respond quickly and not slow down traffic.