But things run in cycles and the publishing business is no exception. Magazines are a great place to break in. Learn the basics of marketing. Some magazines buy all rights. That means you can never sell the story again unless you get the rights back.
Some magazines pay on publication.
That means you won't be paid until your story appears in print. This could take a year or more. A good idea. Barbara Seuling teaches a class on AOL in Children's Writing. Many colleges offer classes as well.