Publishing is really the business of making a person famous enough to sell pulp to the unsuspecting. The fact that it's your baby is of slight concern to the world of business.
You have to approach this with an open mind and realize upfront that YOU are the marketing plan, YOUR bucks float the promo, sales, and YOU have to generate the buzz for your book when you self-publish. Bottom line.
Traditional publishing is the optimum situation if you can get the attention of an agent and they are in thick with major publishers to hawk your book to. The only downside is it is so competitive you might die before the world ever sees your book.
The upside of self-publishing is you have a beautiful bound volume in your hands in a few weeks, no questions asked. Now, the question is how much are you willing to spend to promote it?
Think of everything after the book file is in the computer as marketing and positioning. Your book will be on Amazon - that's part of the deal, which is a good thing. Many self-publishing houses do that nicely, others have schemes to deal with it. Amazon has a hidden charge of about $25 a year if you go to them directly. Of course, their marketing gimmick is to get you to publish with BookSurge, their group, to avoid the fee. To get into the big box stores requires registering with Ingram (and others), which is a service all the self-publishing houses offer. This transfers a copy of your digital file over to their database where they print it out for places like Barnes & Noble, etc. That's just way the system works. Don't ask, but what about... They aren't listening.
Websites, blogs, radio spots, TV interview slots, or any other methods of letting the public know that you exist is the main game. Since traditional publishing has screened its authors via agents and they have decided that your product has a chance on the market, they will do two big things for you 1) have nationwide distribution poised for sales behind a small prime-the-pump run of x-number of books; 2) They will provide some level of promo. That might be a series of signings scheduled, interviews, but unless you're already famous, it will be limited. Then we all sit back and see if it flies. Yes - great. No, don't come back to us, please.
Most new authors don't realize just writings a book of whatever is going to be received by the public with open arms. Get that notion out of your head or you will spend fortune and be ready to jump off a ledge.
Go to some conferences, talk to local authors, join some newsletters that track publishing like Dan Poynter. Get the facts. Shooting in the dark won't work. You'll just shoot yourself in the foot.
OR you can try some poems out on the folks of Fox&Quill, my little website for authors... I think one piece of advice that always plays is start locally and become know as a poet, etc. Do readings. Let people know you are a player. Then, if you self-publish you have people that are most likely going to buy standing around when your first box of books arrives to sell to. If you sell a lot, then the major publishers ears perk up. There is no shame in proving your work can sell and then launching into a deal with a major publisher.
If you just get a book printed, there it sits. What do you really want to see happen? Ask yourself the tough questions. If you are a serious writer, then always be on the lookout for an agent. It only makes sense. If you really want a book in hand to test the water, then spend the $500 and impress your friends, but don't expect a lot of sales. How far can you throw one of your books, is about the size of the sales region we're talking about here.
If your brother runs a chain of major bookstores, then forget everything I said and go that route. It's all about can you draw in sales - that's it. What you write, whether Nobel Prize worthy or how to clean a bicycle is irrelevant. That's the part you personally pine over, but books are like pies, how many can you sell and keep selling??