It's an e-commerce site build by Oscommerce, working on a Unix system.
The workflow for users should be as follows:
1. A user uploads a file to our site and get the counting result with relative charge info.
2. The user click "Place the order".
3. Register (for new user), or login (for returning user).
4. Order confirmation page.
5. A mail contains the order info would be sent to assigned address automatically.
The word counting component is available and also developed with PHP.
The key problem is to build an connection between login function and word counting function. And Paypal could be invited during the checkout.