Drupal, CodeIgniter, Yii or Django for app

My recommendation would definitely be to use Django in this instance, it is extremely well documented, has a very informative community, loads of plugins that can be used, for instance django-paypal for payment integration etc.

Essential tools to get you started and keep you moving quickly!

• Git - svn
• pip - tools, plugins etc
• postgreSQL - no better choice for DB's
• South - database migrations
• heroku - hosting that allows you to focus on developing - recently introduced support for Django / Python

Django is a highly scalable platform that combined with some of the tools listed above creates a kick ass experience.

Hope this helps.

If your main lang is PHP, I would go for CodeIgniter or Kohana . CI is lightweight and easy to learn.

Django/Python is superior IMHO(and provides ORM as opposed to CI), but only if you are willing to learn it, and take the time to set it up correctly (using uwsgi or similar).

In my opinion, django it's the best framework you can use to develop your project, since it's written in python and really easy to learn. Also it teaches you a pythonian way of seeing things which is nice.