I've been reading / studying various guides and documents regarding DNN and my head is spinning so I'm hoping someone can point me in the right direction with this or refer me to a resource that can help. I'm setting up a site where users can subscribe to create their own portal. I'd like to be able to offer various levels of service based on their number of users. So, for example. 1-10, 11-20,21-50,5-100 and so on. They'd come to my portal to sign-up and select a package. Within each package I'd like to offer a selection of skins, modules and containers. For example, it could be that a user signs-up and wants 45 users on their portal with a pack of 10 blue skins and 50 blue containers. Other packages would be available as alternatives / upgrades. I want them to be able to sign up to a trial period and then renew their subscription automatically each month (I've seen several modules I can buy which will enable this part).

The documentation I've been reading is fine in explaining at the micro level how stuff works but what I need is something which will put things in to context so I can work out how best to achieve this and what options I have. Help, would be appreciated.