This is absolutely a sensitive topic. In general, topics talking about money is a sore topic.
As a new freelance writer, I am struggling to charge for every article I write. When I am still juggling a regular 8-5 job, it never crossed my mind how much should I charge because I have fix income. Now, it is taxing. I am in experimenting stage, trying sites like Fiverr, OneSpace, etc. You need to establish your brand identity first online before you charge what you're really worth for. I still have long way to go...