I apologize for any inconvenience in purchasing Constant Contact services.
Constant Contact is a subscription based service and billing is determined by the amount of contacts stored in your account. We do not currently have an option to pay per campaign but I am happy to submit your feedback to the appropriate team. For detailed information about pricing click this link.
We also have a sales team that would be happy to set you up with the right services and avoid the hassle of doing it yourself. You can find their contact information here.
I hope this helps! Please feel free to reach out to us if you have any further questions or concerns.