I know quite a few writers that use sites (like eLance and oDesk) that take a small fee when you get paid. I think those are probably a good place to start out and work to build up a portfolio. That being said, I would NEVER pay for work. Once you get a decent portfolio and create a few samples of the work you can produce, build yourself a website to show yourself off. When you have a professional appearance, you get paid like a professional. Just DO NOT ever bid on everything that comes down the pike. Those that hire freelancers notice this behavior. You could even end up being blacklisted on some of those freelancer sites. (I know a fellow who did that, and here are things to learn from his experience.)
When you are working for a client:
Always keep a professional attitude.
Don't be all hinky and try to get someone to pay you under the table. (This can hurt both of you.)
CHECK your work BEFORE you send it out. If you send badly written work (ie; work that is not spell- checked, work with Bad Grammar, work that looks like you beat the hell out of a thesaurus, etc.) it looks bad on you.
Always see to the client's preference for the type of file you send. Some will want simple .txt, some .pdf, some .doc., etc. Make sure you understand what they want.
Remain In Communication with your client. Every client has different needs and wants, and you give yourself the best advantage when you answer these needs and wants. The only way to know what they want, especially if they are somewhat unclear to you, is to ask questions. There are no stupid question. Clients would rather you ask, than do some crazy dance with you about the work you are producing for them.
WHEW. Hope this helps anyone trying to bust in on the freelancing dealio!