Hi Gale. I charge according to size, and the amount per square inch is determined by how much quilting they want done on their quilt. If it's going to be an easy all-over design that isn't thread-intensive (such as McTavishing) then I charge 2 cents per square inch, and if there's going to be a heavy amount of quilting, or a lot of changes in the designs calling for a lot of starts and stops then I will go as high as 2.5 cents per square inch. So, for a quilt that is 50"x50" for example with light all over quilting it would come to $50 and if it were to have multiple designs or heavy quilting it would come to $62.50.
I don't know what the cost was (that was quoted to you) that made you go "EEK" LOL...but the cost per sq. inch that I posted is pretty much the going rate around here. :)