Hello
there could be many ways to publish your own book with a small cost.
About the editing, you can edit the book yourself or hire a graphic designer that will do for you.

About publishing, I can suggest platforms like amazon or blurb that have their own publishing platforms that allow you to publish and sell on the biggest book platforms and even bookstrore around the world, but your book has to have certain criterias based on the platform you want to use.
The copyright is yours untill you decide to sell it to someone.