sell individual plugins

is there a way to use pro sites as a way to sell the use of individual plugins (not a group of them) to a site?

say you want to offer your users to create a blog for a small setup fee. then give them the option of upgrading their blog like adding seperate plugins to a shopping cart and once paid with paypal, automatically acitivate those plugins on their blog.

also is there a way to only 1 option per plugin, and make it perminent instead of having a end date.