Susan,I've been told to be wary of posting your rates on description sheets you send out (I think this is on the theory that if someone hangs on to one for five years, it will prevent them from getting upset if you've raised the rates). We have on our website a statement that "fees vary depending on time, distance, and other factors." We've gotten a couple thousand dollars for spending a week at a camp/festival teaching and performing, we've played for the hat at a house concert and had a 50 pound sack of potatoes thrown in. I remember hearing that Fairport Convention did a show for a washing machine once.
A description sheet is a great idea.