Themes, Skins, Admin Area and Plugins

Okay. I’ve been poking around WordPress for about a year now off and on. Two months ago I decided to get to know how things actually work. I’ve learned a lot and have styled a few themes and created one of my own. Now I’ve actually created an admin theme that changes the look of the admin area totally. I have some questions related to themeing, plugins, templates and the admin area.

• 1. How does one make money with WordPress if you give away your themes and plugins? I’ve read that support by way of donations are very limited and if you spend 30 hours on a piece of work you would want to get paid for it.
• 2. I’ve gotten to know the admin CSS very well and changed the admin area of my theme to where one wouldn’t recognize it as a WordPress admin area. Is that a bad thing? I’ve heard that it is. I spent a lot of time on it. Shouldn’t I sell it?
• 3. Is a theme just changing the style of another Theme? That seems like a skin to me.
• 4. The “theme” that I’ve created has a lot of functionality that doesn’t come with a lot of WordPress themes. Does that make it a “template”?.
• 5. What is the difference between a theme, a skin and a template?

Thanks in advance for addressing these questions for me.