It depends what you THINK yer worth. Simon Lovell has been known to say the way to get higher fees is to have the balls to ask for them... BUT you have to be able to back it up. You can't charge a grand and suck. Be honest with yourself, get a going rate of YOUR area, and go forth. Don't try to undercut too far. You give everyone else a bad time and they will know and not like you for it.
Also, there is such a thing as perceived worth. Some will not hire you because you charge too LITTLE. "Well he's only 150$, he can't be THAT good. Some people like to brag about the money they spent. Know your clients.
If they sneer at your initial price THEN ask them what their BUDGET is. Not what they are looking to spend and maybe work with them or recommend someone else.
If they sneer at your price, then ask them WHY and then say something like "How about if I lower it to like (insert whatever price here.)." if they still don't budge, then say sorry and send them to somebody else.
You really gotta know what you're worth and that will only come with experience. The more you perform and the better you start feel about your skills and magic, the more you will realize how much you want to start charging.