Thoughts on E-commerce User Generated Content

I’d like to build a WP-based event site where users can pay to post event listings.

Ideally, a user would select one of several event listing types, register for a new account, checkout via PayPal and be granted a role/permission to add one post (of a specific content type). They would then be able to edit their post. To add another post, they would need to purchase another event listing.

There are various modules that focus on e-commerce or user generated content.

Anyone know of an elegant way to connect the two?

Many thanks!

Arthur