The submission procedure for paid applications differs slightly as compared to the submission procedure for free applications.
Note that we are referring to paid applications on the Marketplace and not in-app payments (however, the submission procedure for both paid apps and in-app payment apps is the same).
For the purpose of in-app payments, you can use any third-party service but you will need to take care of the implementation yourself. Firefox Marketplace currently supports only Bango as their payment provider. The following illustration for submitting a paid application:
Now, while submitting paid ...