After years of doing contracting, I've found a general pattern where the clients that wanted to the pay the very least, tended to cause me the most headaches, cause the most scope creep, be the most anal, etc. I also found that doing fixed fee contracts were the most likely to cause both sides problems. I also found another interesting pattern where the clients who treated me with the most skepticism or paranoia ended up being the ones who themselves were the most problematic or dishonest with me. Another pattern I've seen is that whichever side throws out a dollar figure first, almost always "loses" in the negotiations (meaning, gets a deal that is less beneficial to them in terms of dollar cost/income.) General trends, not without exceptions.

Also, there's no such thing as a single standard rate. Varies by skill set, by person, by project, by time/situation, by non-monetary factors (the strategic benefits or opportunity costs of doing a deal/project, etc.) So when someone asks me what's my rate, it signals to me that they are, at least somewhat, a newbie and/or unsophisticated (even if "experienced"). Instead, you tell me what you (think you) want. I tell you whether (I think) I can provide that. We go back and forth. Then somebody (hopefully the other guy) throws out a figure. The other accepts or counter-proposes a different figure/terms. Back and forth. Then shake/sign on something. Move on. Repeat.