What do I need to charge based on custom post types?

I'm redoing a city guide network I have, and bringing everything into WPMU - but I'm new to WPMU and trying to figure out what I need.

So far I've indentified that I'd like to use Custom Press to create my business listings, events listings and coupons as custom post types. And I plan to use Headway for design. And then (finger's crossed) use Gravity Forms to allow editing and submission from the front end of the site.

But I'm stuck on how to recreate the functionality I currently have in my php-based sites for selling upgraded listings and events. Currently, I have (3) levels of listings - each with different features (custom fields I think would do this). One is free, the other two have a fee associated - charged with monthly recurring billing.

So, 2 questions with this really...

1. Do I create separate custom post types for all three Listing Levels?

2. How do I charge and collect payment? MarketPress seems to be for products - but is this what I need?