Heroku charges per second of compute, with no minimum. Using AMQP with https://github.com/the-grid/guv https://github.com/the-grid/guv our average server stays

Heroku charges per second of compute, with no minimum. Using AMQP with https://github.com/the-grid/guv https://github.com/the-grid/guv our average server stays up for just couple of minutes, directly in proportion to current demand