What should I charge?

Hey all,

As a perpetually-broke nonprofit worker, I'm looking into some ways I can bring in a little extra income. When I was undergrad, I used to edit my friends' term papers and other writing assignments, I've been thinking about posting a Craigslist ad and trying to do that for a little extra moolah. I was pretty good at it and helped quite a few friends improve their grades, and since then I've added several years of professional writing and editing experience, so it seems worth trying.

The only problem is I have no idea how much to charge. When I was in college, I used to just do it for six-packs!

Have any of you done this sort of freelancing before? Or have any recent college grads worked with a freelance editor? Any idea what might be reasonable for me to charge?

Thanks for any suggestions.