I started this thing so broke it wasn't even funny. It was, I don't eat during the day because I couldn't afford enough food, paying bills was iffy some months, hope the car doesn't break down, or anyone gets sick, because we'll be in deep hurt.
I had the Internet through my son, an old computer wit Word, and time to research. I learned to do covers on GIMP. I learned to do formatting through looking at stuff on the web, especially Smashword's guide (I didn't do KDP until a few months later). It wasn't easy. It took a lot of time to learn how to do stuff myself, and do it well enough to sell anything at all.
At any rate, if I were starting today, I'd write in Word, use D2D to format, GIMP for covers, and focus on ebooks through KDP. I wouldn't worry about print or audio, IS, or anything else until I got good enough to sell ebooks that would cover the price of anything else. I would have learned how to do proper covers first, how to write a good description, how formatting should be.
This would mean a crap ton of work. If it turned out I couldn't do covers, I'd look into cheap but appropriate premade covers, and try to save up for them. This means not publishing as quickly, most likely, but that's how it works.
To be honest, I'm not sure it would be possible today to start and spend no money at all. Ads really need to be done, and people like me who have no social media skills wouldn't have that option, unless we could learn to be good at one platform or another. Most people can't edit their work, they can't do covers, formatting seems to be an issue, though for ebooks, the simpler the better.
So, I say that while it's still technically possible, it's going to be a long, hard haul through learning to write first, and then be a good publisher, because in the end, the publishing really isn't that different, it's just all on us.