Founder @MagikPress, Lead Web Dev @Winculum. WordPress Developer, UI/UX hacker, Free Software activist, Doctor Who Fan, and all-around geek.
I'll help you with leveraging WordPress for you web presence, covering everything from themes, plugins, SEO, performance, web hosting, server setup, etc.
One of the most sucessful models for premium plugins is to offer a core plugin for free then allow installing add-ons. These premium add-ons could be created by you or the community. For successful examples, see Easy Digital Downloads, Ninja Forms and Woocommerce.