It used to be that in order to self-publish, you had put down a lot of money for a lot of copies that may or may not ever be bought. But with the advent of Kindle and other eBook readers, all that has changed.
After writing my Th.M thesis about evangelistic methods, I really wanted to have people read it, so I sent the PDF to some people I knew. But then I discovered that I could publish directly to Amazon’s Kindle store, at zero cost and without a publisher. Amazon is the big name in buying books these days, but I thought that in order to get on Amazon, you had to be a real publisher, not just somebody off the street. I also thought that in order to make an eBook, you had to have some kind of fancy technical skills (or the money to pay to some who does). I was wrong on both counts.