I need two registration forms. One for the general public, Consumers Group A, and one for Trade Partners Group B. The Trade Partners will have extra pages and be able to shop for documents that they can purchase singly or in multiples (shopping cart). There is no membership fee for Group B to join, but only Group B can register to buy online documents, the Consumer Group A can only be a consumer member and upload forms, and they cannot see the extra pages, documents for sale or shopping cart.

Is this my best solution, or do I need something else?

CBSubs and DocMan sounds like a great combination for your needs.