I looked at the following services: Kong Community Edition, Amazon API Gateway, 3scale API Management Platform, TIBCO Mashery API Gateway, Apigee API Management, Tyk… It doesn't look like any of those companies include billing out-of-the-box. (Amazon seems to be the closer one by offering access to its marketplace.)
Am I missing this feature in any of the options mentioned above? If not, is there another solution for it out there? Anything else that you would recommend?