[JeremyReimer]

Quote: "self-publishing well is expensive (four, five digits easily)"

This is basically correct, although it depends on the definition of "well". You can get a halfway decent cover for $100-$500, and you can get a halfway decent copy editor for about $500-$1000. Tools like Scrivener can handle all the ebook and paper edition formatting for you, with built-in templates, so that's another $100 or so for the tooling, but you can reuse this for future books. Publishing to Amazon and other places (like Smashwords) is free, and this includes print-on-demand paperback copies as well.

What it does take is a lot of time for learning how to use all the tools and to navigate the many options available for covers, editing, etc.

As far as marketing expenses go, there are no good ways to spend money to sell books. I think you're correct that nobody knows how to do it. If you don't win the lottery and get featured on a celebrity's book club, how is anyone supposed to ever know that you even released a book?

[ghaff]

I'd say you can get the mechanics taken care of for the low four-digit figures. Publicity and marketing? The sky is the limit if you don't already have a following. I get a ton of requests for podcasts and interviews related to books. Which I 95% ignore. You probably want to do marketing yourself which is a major undertaking and probably won't work.