Most authors are not marketing managers or sales people; all they want to do is write.
That is why Cooperative Publishing (co-op) is so great in my opinion.
Now first I will tell you what you are going to both read & hear when you do your research (& by all means; I encourage you to do just that).
"If they want your book; they'll pay you" or "A real publishing house doesn't charge for books to be published".
You'll see phrases like "Vanity Press", "Scam"... the list goes on.
Every author wants to believe they are ready for the big boys; but the reality is, they aren't.... but they still may have a really good book or have something to say.
For these authors; I recommend co-op publishing or subsidy publishing. It is where your book is evaluated (just like in traditional publishing) for it's estimated expense of publication & for it's marketability.
Authors are asked to supplement only 10% of the estimated cost up front.
The trade off?
Higher royalty rate.
You get to keep all rights to your book.
You get all the distribution, reviews & other benefits of a traditionally published book.
In about half the time and at a much greater acceptance ratio.
You get to be sold right in the same venues as the big boys while maintaining the integrity & freshness of a new talent.
So at 10% of the cost of self publication & all the kudos of traditional publication... co-op contracts are the best of both without the pitfalls of either.