Premiere Elements is for editing videos (as well as videos that include photos).
Photoshop Elements is for editing photos and other graphics.
The Organizer (which comes bundled free with either and both programs) is a media file management tool that interfaces with both programs.
Premiere Elements and Photoshop Elements are standalone programs. Each comes with an Elements Organizer. When both those products are the same version and are on the same computer, they share the same Elements Organizer and there is a defined degree of integration between the two.
* Premiere Elements is only for videos, and Photoshop Elements only for photos?
You can import photos (even raw format or dng files with right version of Camera Raw installed) as well as videos into your Premiere Elements project, for edit and export. You cannot import videos into the Photoshop Elements Editor.
You can purchase Premiere Elements 14 and Photoshop Elements 14 separately. Or you can purchased them bundled together. When bundled together the price is less than the price of each separately purchased.
Please consider the above. If any questions or need clarification on the above, please do not hesitate to ask.