My freelance business continues to chug along -- I'll never get rich from it, but I bring in a little extra cash to pay for fun.
I go through elance.com, where jobs are posted, I bid on them, and the buyer chooses someone for their job based on the amount of the bid, a written proposal and the time it will take you to finish the project.
The written proposal is no problem. Neither is the time (I am a very fast worker). But I am often unsure of how much to bid pricewise. Too high and I know I will not get the job. Too low and I am wasting my time. However, someone is almost always lower than me. I figure out how much I want to make per hour and bid that. I bid about the hourly rate I make at my full-time gig, but of course the freelance gigs have no benefits. I read often that I should get more -- people would refuse to work for my wage. But honestly, I need the money and the challenge from the freelance.
I adjust my rate as needed. I feel OK about it now, but I wonder if I won't look back someday and wish I got more.