Paypal Payment From DB Data

We are running a database with user information. Each user has a personal and unique identification code. We need a simple setup: 1. User enters his/her unique code. 2. All the information in the database is printed back for verification on a simple page. 3. Also, in the DB is the value (€) the user needs to pay; 4% should automatically be added to this (to off set Paypal costs). This value should be printed on the same page with an accept button. 4. If the user accepts, the necessary information is sent to Paypal to open up the payment page where they simply have to enter their username/password or creditcard information to complete payment. The description for the payment needs to include the unique code. Though the project description is long it should be very easy for someone with a working paypal knowledge.