As @blueeyes8960 says, you can post anything you want as long as you own the right to it. A lot of people re-post their Steemit content. I've done it too.

The $15 fee is only for getting certified. You don't have to do that. You can post right out of the gate. If you go to and page on the site, you'll see your profile pic in the upper right corner--just like on Steemit. Right next to it, on the left, is a little square icon with a pencil in it (on Steemit, it's a circle--same concept). Click on that square with a pencil in it and you'll go to your posting panel. The UI is considerably better than on Steemit.

What is your profile name on Narrative?