You can self puish both ebooks and paperbacks on Amazon KDP. The royalties are actually great, especially on the paperbacks but ebooks too, to be honest - far higher than traditional publishing (I have done both) - of course, the disadvantage is that it's very difficult to market a self published book unless you have a large platform. What is the intended audience of your book?
It's very easy to do once you do some research - no fees involved unless you want to pay out for editors, book cover design or typesetting. It is possible to do all those things yourself, though, depending how good you are at design. Canva is a very useful tool.
Second asking kboards, also indie writers boards on Goodreads.