A great way way to start out in my opinion is to look at your local publications and see if you can write something for them. Almost every place has a local parenting magazine or regional magazines that are often free at places like the library, etc. Some of these publications don't pay, some do. If you live in a small town and don't have anything like this, just look to the next biggest town. You have something somewhere. I would first ascertain if these publications hire freelance writers. You can do that by looking at the masthead and then looking at the names of authors on the articles. If they are the same names, that means that they do most of their writing in-house and, while they may sometimes hire freelancers, a lot of their articles are written by the editors. Then I would come up with a few ideas for one of these publications and write a query. For the most awesome and helpful information on query writing, I highly recommend The Renegade Writer, both the website and the book, and the Renegade Writer's Query Letters that Rock. You also asked about internships online. Taking a class from the Renegade Writer author, Linda Formichelli, especially her Getting Started in Magazine Writing, is AWESOME. I understood so much more about the industry after doing her class. I highly recommend doing the option where you get feedback from her and can email her back and forth with your questions.http://www.therenegadewriter.com/http://www.therenegadewriter.com/que...s-that-rocked/http://writeformagazines.com/
The Renegade Writer website is awesome, but I highly recommend buying both of their books, they are well worth it and not expensive at all.
Yes, you cam freelance and make a living at it and write from home. It is definitely doable, but it takes a lot of persistence and you have to always be working at it, because you are essentially always looking for a job. You don't have an employer sitting there handing you work to do. You have to go out there and get it.
ETA: The reason why I think it is great to start with regional pubs is because it is usually a lot easier to break into them, and then it gives you clips to go out and write for other places.