R Ranson is definitely a good person to listen to about this. I self-published a book this year also, so it's very fresh in my mind too.
It's possible to just write anything, not edit it or format it well, and publish it for free on Kindle Direct Publishing (aka Createspace). This is what gives self publishing a bad name.
It's also possible to get freelance editors, proofreaders, and graphic designers involved and to publish something that is just as good (or better) than anything that's being published by a traditional publishing company. I found
this website recently and think it would be good for authors to find the right freelancers and not get ripped off, but I don't have experience with it myself. Posting on the
jobs offeredforum of Permies might help you find good freelancers too.
There's also vanity publishers, which sound really nasty.
I published with IngramSpark, which suited me as I'm a freelance graphic designer, reasonably computer literate, and could work with their guidelines. Some people that aren't good with these things complain that IngramSpark doesn't hold their hand enough through the process, or that their wording isn't clear enough, but I had no problems at all, and when I did need help from them, they answered my questions pretty quickly and were clear in their answers.
Promoting a self-published book can be tricky, I find it really difficult as I'd much rather be working creatively on new stuff - I am a writer, not a saleswoman. This is a huge benefit of traditional publishing deals, as they have someone there that is good at selling and promoting books.
This is R Ranson's book:
https://www.etsy.com/ca/listing/673745296/homegrown-linen-transforming-flaxseed
This is my book:
https://www.amazon.com/Backyard-Dairy-Goats-Natural-Approach/dp/0648466108/