title: How to sell subscriptions with Django?
body: <p>I have to develop an application for selling web-services. I have 2 goals:</p>
  
  <p>1) Any customer can subscribe to a service and using within a month having paid for it.</p>
  
  <p>2) Any customer can pay for a e-content and study it unlimited time.</p>
  
  <p><strong>Are there external libraries for Django to do it?</strong></p>