Establishing your rates and my thoughts...
Your competitive edge. Depending on where you live, there may be a lot of competition for this area of work (web development, design, seo and so on...). How you stack up against the competition - in terms of quality, services, experience, skills, location, rates etc., greatly affects your bottom line.
How much time you invest into the business is also important to in sorting our how much to charge.
Finally – what do you need to live? Taking all these factors into account your going to find your bottom line. In that you find the area in which you can remain competitive against your competition.
You can ask everyone here what they charge for this and that, but what is most important is to have a business plan set with your budget to survive intact.
I have seen this post so often on WmW. You are running a business, and to do so… you have to devise a plan, and what it will take for you to survive in order to see that plan through.
Hope this was some help…