You just have to go with what works in your area. One person will say it's to cheap, and the next one will think it's to high. I have been doing shows for several years, and you just have to play the game and see what works out for you.
First you need to realize that you can't get what your items are worth in todays market (unless you live in a crafty area) second just go for a fair price that will give you profit and not hurt the buyer. I did a craft fair and was told my quilts were to cheap but it was what i was comfortable charging. Keeping in mind the cost of your supplies. i.e., I charged $7.50 for an embroidered kitchen towel and people snatched em up left and right. The towels were $4 for 3 to buy blank, soooooooo - let your conscience be your guide.......;-)