There's a really great book that explains this and gives you some tips about going about it - and it's permafree! It's called "Reader Magnets" by Nick Stephenson. You can find it on Amazon here.
ETA a word I left out.
I have a PO Box away from my home from before I started writing, so I use that one. I've seen one or two people say that they just use their home address. I guess it just depends on how comfortable you are with having it out there. The minuscule chance of some deranged person knowing where I live is enough for me to not want to use my home address but maybe I'm being paranoid. Still, I figure better to just pay for a PO Box than have to move to avoid stalker obsessed with me and my beautiful prose.
Personally, I haven't seen huge returns from my mailing list--I only have about fifty subscribers so far. But from everything I hear and read they are an enormous resource and one of the few things you should definitely have.
I mean, imagine being able to email a group of people who are specifically interested in your work every time you release a title--and then get a bunch of sales from them, and then get the boost in rank for you book that they would give.
I wouldn't let not having a mailing list keep you from publishing--if it is. But I'd say it's worth setting up. Check out <em>Reader Magnets</em>. It's free on Amazon and it sells the importance of a mailing list better than I could.
A PO Box is definitely an expense, but if you're planning on doing this as a business--as a career--rather than I hobby, I'd say basically: suck it up, if at all possible. It's just one of those things you need to spend money on. Lol, I feel like my dad saying, "suck it up."
Check out the free Amazon BookReader Magnets by Nick StephensonHe pretty much explains how to do this step-by-step, using a free book as the reward to opt-in.
Great functional marketing detailed insights and tips in this FREE ebook! https://www.amazon.com/dp/B00PCKIJ4C Summary: Networking, brand building, FOMO, and value-add marketing.
You should just check his out:
https://www.amazon.com/Reader-Magnets-Platform-Marketing-Authors-ebook/dp/B00PCKIJ4C