I have had the same problem. People don't understand the time and effort that go into doing things by hand, whether it is the woodwork or the quilting.
I finally started giving a bid on a quilt project, just as a contractor does on remodeling:
$ amount for materials
$ amount for time with an estimate of hours involved
$ amount for printing pics on fabric
$ amount for piecing, quilting
or whatever, to give people an idea of what they are really getting. Yes, some have not come back to have the work done. But at least they know what they are giving up.
I hope a little education will help others see how valuable the art of quilting really is.