Depends on the type of bundle, Steam has two. The original style, you paid for everything in the bundle. The new style, it excludes items you already own resulting in a discount.
Here is an example of the new bundle type (viewed on an alt, since I owned all of those :P), you can see the difference at the bottom. https://i.imgur.com/J2QXFh6.png
Yeah. That's why I added more stuff. Getting some DLC. ---
