The term is changing. What used to be self-pub can take new forms.
Until now, I have resisted self-pub. But after several years and no success selling my novels to a traditional pub house, I yield.
I was in a writers group for years and know quite a few people who self-pub. They all have one thing in common, they hold up a book and claim to be 'published'. I don't call that being published.
Most common is to just pay somebody to print (publish) your book.
Another is to go with somebody like Publish America. They will publish your book and send you a $1.00 bill. You give up all rights but will see a book with your name on it.
I am about to 'publish' with Amazon Kindle and Amazon books. Kindle pays fairly well for each e-book sold and you keep your rights. Amazon books is a print-on-demand publisher. When someone buys they get a real book and you get paid the princely sum of 33 cents per copy. But you do keep your rights.
I'm not really answering your question.
The only experience I can share is second hand. They get a copy of their book with their name on it and all seem happy.