children's book; I want to write my own?

You have to write it first. Start with a good idea, well developed characters; each with a back-story. The genius is in the details. It makes the story so much more believable. Once it's done, shop it around to different publishers and hope one of the editors likes it--a lot. J.K. Rowling shopped HP to many publishers before Scholastic finally picked it up. Don't worry about the money in the beginning and don't let it be your impetus to write. Write the story because you like it and you want to tell it. The rest will take care if itself.

try here

www.rosedog.com

you can self publish here, they dont charge you, they take a small percentage from each book you sell, theres no waste cus they print to order and you have a choice of ordering in all formats, hardback, paperback, ebook etc... worth taking a look

you are in control of the pricing etc

I suggest you go to your local library. Ask the librarian and she probably have an idea or two. Goodluck.